RU2310280C9 - Method for transmitting-receiving data in radio communication system (variants), method for evaluating correlation interval of received orthogonal frequency-multiplexed symbols (variants) and device for realization of methods (variants) - Google Patents

Abstract

FIELD: radio engineering, possible use in local wireless networks in 802.11 standard, telecommunication systems in 802.16 standard, and also in other OFDM (Orthogonal Frequency Division Multiplexing) systems.

SUBSTANCE: in known OFDM systems, distance connections between pilot symbols in time and frequency areas are predetermined fixed values. However, maximal signal delay in multi-beam channel and Doppler shift of the signal may vary. Distance between pilot symbols in time and frequency areas is selected, as a rule, for largest maximal signal delay in multi-beam channel and largest Doppler signal shift. This results in reduction of transmission speed of useful information in communication system. Therefore in the claimed invention distances between pilot symbols in time and frequency areas are variable values, which change depending on maximal signal delay in multi-beam channel and Doppler signal shift.

EFFECT: increased speed of data transmission in communication systems.

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Description

The group of inventions relates to radio engineering, in particular to a method of transmitting and receiving data in a radio communication system (options), a method for estimating the correlation interval of received orthogonal multiplexed symbols (options) and a device that implements them (options), and can be used in local wireless networks using standard 802.11, telecommunication systems standard 802.16, as well as in other OFDM systems (OFDM Orthogonal Frequency Division Multiplexing - orthogonal frequency multiplexing).

In OFDM systems, pilot symbols are used for coherent signal reception. Typically, the distance between the pilot symbols in the frequency domain equal to N _F Δf, where N _F is the number of modulated data symbols located between the pilot symbols in the frequency domain, and Δf is the frequency shift between subcarriers of the orthogonal frequency-multiplexed symbol, is chosen as so that in the frequency interval N _F Δf the pilot symbols are noticeably correlated with each other, for this the specified frequency interval must satisfy the inequality

where τ _{max is the} maximum signal delay in the multipath channel.

And the distance between the pilot symbols in the time domain, equal to N _T Δt, where N _T is the number of modulated data symbols located between the pilot symbols in the frequency domain, and Δt is the duration of the orthogonal frequency-multiplexed symbol, is chosen so that in the time interval N _T Δt pilot symbols were noticeably correlated with each other, for this the indicated time interval should satisfy the inequality

where B _{d is the} maximum Doppler shift of the signal (Richard van Nee, Ramjee Prasad, OFDM Wireless Multimedia Communications, Artech House, Boston-London, 2000).

An example of the arrangement of pilot symbols shown in figa. The time structure of orthogonal frequency-multiplexed symbols is shown in FIG. 1b, where Tg is the duration of the guard interval, T _N is the duration of the signal obtained after the inverse fast Fourier transform. For example, for 802.16, the guard interval is T _g = 11.2 μs (128 samples), and the transmitted symbol is T _N = 89.6 μs (1024 samples) (Richard van Nee, Ramjee Prasad, OFDM Wireless Multimedia Communications, Artech House, Boston-London, 2000).

Another example of the arrangement of pilot symbols is given in the book (Richard van Nee, Ramjee Prasad, OFDM Wireless Multimedia Communications, Artech House, Boston-London, 2000).

There are various methods and devices for transmitting and receiving data in a radio communication system and devices for their implementation, for example, the method and device described in the article [Michele Morelli and Umberto Mengali. A comparison of pilot-aided channel estimation methods for OFDM systems. IEEE transactions on signal processing, vol. 49, no.12, December 2001].

In this method, a sequence of modulated data and pilot symbols is transmitted to the transmitting station. In this case, the pilot symbol is repeated every N _f modulated data symbols.

The sequence of modulated data and pilot symbols is converted into parallel groups of modulated and pilot symbols, each of which consists of Q modulated symbols and K pilot symbols.

Groups of modulated and pilot symbols are complemented with sequences consisting of Z zero symbols, placing them at the beginning and end of the group. Moreover, N = Q + K + 2Z.

Each group performs the inverse fast Fourier transform, then IFFT, forming parallel output groups of IFFT values.

Convert the parallel output groups of IFFT values into serial form, thus forming a sequence of transmitted characters, each of which contains N received IFFT values.

Each transmitted symbol is supplemented with a guard interval, thus forming a sequence of orthogonal frequency multiplexed symbols.

A sequence of orthogonal frequency multiplexed symbols is transmitted to the receiving station.

At the receiving station, they are received and the guard interval is removed, thus forming a sequence of received symbols.

Convert received characters to parallel groups of input values.

An FFT is performed with each group of input values, thus forming N modulated symbols in each group.

In each group, pilot symbols perform a communication channel estimate.

Using the obtained communication channel estimation results, demodulation of the obtained estimates of modulated data symbols is performed, thus forming a sequence of binary data.

A device that implements the proposed method includes a transmitting station and a receiving station. The transmitting station contains a block of serial-parallel conversion of a sequence of modulated data symbols and pilot symbols into parallel groups, a block for supplementing these parallel blocks with sequences of zero symbols, an IFFT block, a parallel-serial conversion unit (converting parallel output groups of IFFT values into serial form), and a block attaching a guard interval (supplementing each transmitted character with a guard interval). The receiving station contains a series-parallel-parallel conversion unit (conversions, received characters into parallel groups of input values), a guard interval removal unit, an FFT unit, a channel estimation unit, and a demodulation unit.

The disadvantage of this technical solution is that the distances between the pilot symbols in the time and frequency domains are predetermined fixed values. The distance between the pilot symbols in the frequency domain is selected for the largest maximum signal delay in the multipath channel. However, the maximum signal delay in the multipath channel may be reduced. In this case, the number of pilot symbols becomes redundant. In the time domain, the pilot symbols continuously follow each other, which also increases the redundancy of the number of pilot symbols. The transfer of redundant overhead information reduces the transmission rate of useful information in the communication system.

The closest technical solution to the claimed invention are the method and device described in the article [Sinem Coleri, Mustafa Ergen, Anuj Puri and Ahmad Bahai. Channel estimation techniques based on pilot arrangement in OFDM systems. IEEE transactions on broadcasting, vol. 48, no.3, September 2002.]

A known method is as follows

The transmitting station receives a sequence of binary characters. The sequence is divided into words consisting of d characters (d = 1, 2, ..., D).

Each word is assigned a modulated data symbol in the form of a complex number.

Convert a sequence of modulated data symbols into parallel groups of modulated symbols.

In parallel groups of modulated symbols, pilot symbols are placed between the modulated data symbols, thus forming a sequence of groups, each of which consists of N modulated symbols, N = Q + K, where Q is the number of modulated data symbols in the parallel group, K is the number of pilot -characters in a parallel group.

OBPF is performed with each group, forming parallel output blocks of OBPF values.

Supplement each block of OBPF values with a guard interval.

Convert parallel blocks of OBPF values with a guard interval into a serial form, thus forming a sequence of transmitted characters, each of which contains N received OBPF values.

A sequence of orthogonal frequency-multiplexed symbols is transmitted to a receiving station.

At the receiving station, they are received, converted into parallel blocks of input values and the guard interval is removed.

A fast Fourier transform is performed from each group of input values, thus forming N modulated symbols in each group.

In each group, pilot symbols perform a communication channel estimate.

Using the obtained results of the evaluation of the communication channel, an evaluation of the modulated data symbols is performed, forming blocks of estimates of the modulated data symbols.

The group of estimates of the modulated data symbols is converted into a serial form, thereby forming a sequence of estimates of the modulated data symbols.

Demodulation of the obtained estimates of the modulated data symbols is performed, thereby forming a sequence of binary data.

The structural diagram of a device that implements the described prototype method is made in figure 2

A device that implements the prototype method (figure 2) contains a transmitting station 1 and a receiving station 2, which are connected via a communication channel 3, while the input of the transmitting station 1 is the input of the device, the output of the receiving station is the output of the device, the output of the transmitting station 1 is connected with the input of the receiving station 2 through the communication channel 3,

the transmitting station 1 comprises a modulator 4, a serial-parallel conversion unit 5, a pilot signal installation unit 6, an inverse fast Fourier transform unit 7, a guard interval 8 attachment unit, a parallel-serial conversion unit 9, a transmitter 10, wherein the input of the modulator 1 is the input of the transmitting station 1, the output of the modulator 1 is connected to the input of the serial-parallel conversion unit 5, the outputs of which are connected to the inputs of the installation block of the pilot signals 6, the outputs of which are connected to Dams of the inverse fast Fourier transform block 7, the outputs of which are connected to the inputs of the attachment block of the guard interval 8, the outputs of which are connected to the inputs of the parallel-serial conversion block 9, the output of which is connected to the input of the transmitter 10, the output of which is the output of the transmitting station and connected to the channel input communication 3,

the receiving station 2 comprises a receiver 11, a serial-parallel conversion unit 12, a guard interval removal unit 13, a fast Fourier transform unit 14, a channel estimator 15, a parallel-serial conversion unit 16 and a demodulator 17, while the input of the receiver 11 is the input of the receiving station 2, which is connected to the output of the communication channel 3, the output of the receiver 11 is connected to the input of the serial-parallel conversion unit 12, the outputs of which are connected to the inputs of the removal unit of the guard interval 13, the outputs of orogo connected to the inputs of a fast Fourier transform unit 14, the outputs of which are connected to the inputs of the channel estimation unit 15, which outputs are connected to the inputs of a block parallel-to-serial conversion 16, whose output is connected to the input of a demodulator 17 whose output is the output of the receiving station.

The prototype device (figure 2) works as follows.

The transmitting station 1 receives a sequence of binary characters. In modulator 4, a sequence of binary characters is divided into words consisting of d characters (d = 1, 2, ..., D). Each word is assigned a modulated data symbol in the form of a complex number.

In the series-parallel conversion unit 5, the sequence of modulated data symbols is converted into parallel groups of modulated symbols.

In the pilot installation block 6, pilot symbols are arranged in parallel groups of modulated symbols between the modulated data symbols, thereby forming a sequence of groups, each of which consists of N modulated symbols, N = Q + K, where Q is the number of modulated data symbols in parallel group, K is the number of pilot symbols in the parallel group.

In block OBPF 7 with each group perform OBPF, forming parallel output groups of values OBPF.

In the attachment block of the guard interval 8, the parallel output groups of IFFT values are supplemented with a guard interval.

In the parallel-serial conversion unit 9, parallel output groups of IFFT values with a guard interval are converted into a serial form, thereby forming a sequence of orthogonal frequency multiplexed symbols.

A sequence of orthogonal frequency-multiplexed symbols is transmitted from the output of the transmitter 10 via the communication channel 3 to the receiving station 2.

At the receiving station 2, they are received through the communication channel 3 in the receiver 11, and the received frequency-multiplexed symbols are converted into parallel groups of input values in the serial-parallel conversion unit 12.

In the guard interval removal unit 13, the guard interval is deleted.

An FFT is performed with each group of input values in the FFT block 14, thus forming N modulated symbols in each block.

In the channel estimator 15 in each group, the pilot channel is evaluated by the pilot symbols. Using the obtained results of the evaluation of the communication channel, an evaluation of the modulated data symbols is performed, forming groups of estimates of the modulated data symbols.

In the block parallel-sequential conversion 16 convert the group of estimates of modulated data symbols in serial form, thus forming a sequence of estimates of modulated data symbols.

In the demodulator 17, demodulation of the obtained estimates of the modulated data symbols is performed, thereby forming a sequence of binary data that is output from the demodulator 17 to the output of the receiving device 2.

The disadvantages of the method and the prototype device is that the distances between the pilot symbols in the time and frequency domains are predetermined fixed values. The distance between the pilot symbols in the frequency domain is selected for the largest maximum signal delay in the multipath channel. However, the maximum signal delay in the multipath channel may be reduced. In this case, the number of pilot symbols becomes redundant. In the time domain, the pilot symbols continuously follow each other, which also increases the redundancy of the number of pilot symbols. The transfer of redundant overhead information reduces the transmission rate of useful information in the communication system.

In known OFDM communication systems, the distances between the pilot symbols in the time and frequency domains are predetermined fixed values. The distance between the pilot symbols in the time and frequency domains is chosen, as a rule, for the greatest maximum signal delay in the multipath channel and Doppler signal bias. However, the signal delay in the multipath channel and the Doppler shift of the signal can vary. In this case, the number of pilot symbols becomes redundant. The transfer of redundant overhead information reduces the transmission rate of useful information in the communication system.

Therefore, in the proposed group of inventions created in a single inventive concept, the distances between the pilot symbols in the time and frequency domains are variables that vary depending on the maximum signal delay in the multipath channel and the Doppler signal bias.

To implement the proposed method of data transmission-reception in a radio communication system, it is necessary to evaluate the value of the correlation interval, which can be performed in various ways.

The prior art methods for estimating the magnitude of the correlation interval, for example, two methods that are described in the book [V. Tikhonov Statistical radio engineering. M .: Radio and communication, 1982].

In the first method, the correlation interval is geometrically equal to the base of a rectangle with a unit height and an area equal to the area enclosed between the curve of the normalized correlation function when the argument value of this function is greater than zero and the abscissa axis.

In the second method, the correlation interval is equal to the value of the argument at which the value of the normalized correlation function is 0.1.

Closest to the claimed method of estimating the correlation interval of the received orthogonal multiplexed symbols (options) is the second version of the method described by [Tikhonov V.I. Statistical radio engineering. M .: Radio and communication, 1982].

However, these methods for estimating the magnitude of the correlation interval are not applicable when estimating the correlation interval in the frequency domain adopted under multipath conditions and in the presence of noise of orthogonal frequency-multiplexed symbols.

The objective of the invention is to increase the data rate in OFDM communication systems.

To solve the problem, two variants of a method for transmitting and receiving data in a radio communication system (for the frequency and time domains), two variants of a method for estimating the correlation interval of received orthogonal frequency-multiplexed symbols (for the frequency and time domains) and, respectively, for the first and second embodiments of the method are claimed claimed device (options).

The inventions are combined into a group of inventions, because they were created in a single inventive concept, aimed at solving one technical problem - improving the speed and quality of data transmission in OFDM communication systems. To obtain the best technical effect, their combined use is advisable. However, it is not excluded (possibly) that they can be applied separately for the variants (respectively, for the frequency and time domains).

The problem is solved by the claimed method of data transmission-reception in a radio communication system according to the first embodiment, which consists in the fact that

the transmitting station receives a sequence of binary characters,

the sequence is divided into words consisting of d characters, where d = 1, 2, ..., G,

each word is assigned a modulated data symbol in the form of a complex number,

converting a sequence of modulated data symbols into parallel groups of two types, the first of which consists of Q1 modulated data symbols, where Q1 is a given number, the second is from Q2 modulated data symbols, where Q2 is a given number,

complement groups of the first kind with sequences consisting of Z zero characters (zeros), placing them at the beginning and end of the group, with Q1 + 2Z = N,

complement the second type of group with sequences consisting of Z zero characters, placing them at the beginning and end of the group, and every N _f modulated data characters have a pilot symbol, where N _f = Q2 / K, with Q2 being a multiple of K and Q2 + 2Z + K = N, and K is the number of pilot symbols in the group of the second kind,

form a sequence of groups of the first and second types in such a way that groups of the second type follow every N _t groups of the first type, where N _t is a given number, while in groups of the second type that are separated from each other by a given number V of groups of this type, the number of modulated data symbols N _f located between the pilot symbols is assigned the minimum predetermined value N _f = N _{f min} ,

each group of the generated sequence performs the inverse fast Fourier transform, forming parallel output groups of values of the inverse fast Fourier transform,

converting parallel output groups of values of the inverse fast Fourier transform into a serial form, thereby forming a sequence of transmitted characters, each of which contains N received consecutive values of the inverse fast Fourier transform,

supplement each transmitted symbol with a guard interval, thus forming a sequence of orthogonal frequency-multiplexed symbols,

transmitting a sequence of orthogonal frequency multiplexed symbols to a receiving station,

they are received at the receiving station and the guard interval is removed, thereby forming a sequence of received symbols,

convert the received characters into parallel groups of input values,

a fast Fourier transform is performed with each group of input values, thus forming N modulated symbols in each group,

the pilot symbols of the groups of the second type, in which the number of modulated data symbols located between the pilot symbols N _f assigned the minimum value N _f = N _{f min} , evaluate the correlation interval of the received modulated symbols in the frequency domain N _{f cor} normalized to the frequency shift between subcarriers of the orthogonal frequency multiplexed symbol,

transmitting the obtained estimate of the duration of the correlation interval in the frequency domain to the transmitting station,

in each group of the second type, pilot symbols are used to evaluate the communication channel,

using the obtained communication channel estimation results, Q1 modulated data symbols of the first-type groups and Q2 modulated data symbols of the second-type groups are evaluated,

converting the group of estimates of the modulated data symbols in serial form, thereby forming a sequence of estimates of modulated data symbols,

performing demodulation of the obtained estimates of the modulated data symbols, thereby forming a sequence of binary data;

at the transmitting station, the value of N _{f is} adjusted so that the condition N _f <N _{f cor is} satisfied _, where N _f is the number of modulated data symbols located between the pilot symbols, and N _fcor is an estimate of the duration of the correlation interval in the frequency domain.

The problem is also solved by the claimed method of data transmission-reception in a radio communication system according to the second embodiment, which consists in the fact that

a sequence of binary characters arrives at the transmitting station, the sequence is divided into words consisting of d characters, d = 1, 2, ..., G,

each word is assigned a modulated data symbol in the form of a complex number,

converting a sequence of modulated data symbols into parallel groups of two types, the first of which consists of Q1 modulated data symbols, where Q1 is a given number, the second is from Q2 modulated data symbols, where Q2 is a given number,

complement the groups of the first kind with sequences consisting of Z zero characters, placing them at the beginning and end of the group, with Q1 + 2Z = N,

complement the second type of group with sequences consisting of Z zero characters, placing them at the beginning and end of the group, and every N _f modulated data characters have a pilot symbol, where N _f is a given number, with Q2 being a multiple of K and Q2 + 2Z + K = N, and K is the number of pilot symbols in the group of the second type,

form a sequence of groups of the first and second types in such a way that groups of the second type follow every N _t groups of the first type, where N _t is the number of modulated data symbols located between the pilot symbols in the time domain, with a given period T ₁ in during a specified time T ₂ assign the number of modulated data symbols located between the pilot symbols in the time domain, the minimum specified value N _t = N _tmin ,

each group of the generated sequence performs the inverse fast Fourier transform, forming parallel output groups of values of the inverse fast Fourier transform,

converting parallel output groups of values of the inverse fast Fourier transform into a serial form, thereby forming a sequence of transmitted characters, each of which contains N received consecutive values of the inverse fast Fourier transform,

supplement each transmitted symbol with a guard interval, thus forming a sequence of orthogonal frequency-multiplexed symbols,

transmitting a sequence of orthogonal frequency multiplexed symbols to a receiving station,

they are received at the receiving station and the guard interval is removed, thereby forming a sequence of received symbols,

convert the received characters into parallel groups of input values,

a fast Fourier transform is performed with each group of input values, thus forming N modulated symbols in each group,

on the pilot symbols of the second kind of groups that are transmitted with a predetermined period T ₁ for a predetermined time T ₂ , when the number of modulated data symbols located between the pilot symbols in the time domain takes a minimum predetermined value N _t = N _{t min} , evaluate the duration the correlation interval in the time domain N _tcor normalized to the duration of the orthogonal frequency-multiplexed symbols, the received modulated symbols,

transmitting the obtained estimate of the duration of the correlation interval in the time domain to the transmitting station,

in each block, the pilot symbols are used to evaluate the communication channel,

using the obtained communication channel estimation results, Q1 modulated data symbols of the first type groups and Q2 modulated data symbols of the second type groups are evaluated,

converting the group of estimates of the modulated data symbols in serial form, thereby forming a sequence of estimates of modulated data symbols,

perform demodulation of the obtained estimates of the modulated data symbols, thereby forming a sequence of binary data,

at the transmitting station, the value of N _{t is} adjusted so that the condition N _t ≤N tcor is _satisfied , where N _t is the number of modulated data symbols located between the pilot symbols in the time domain, and N _tcor is the duration of the correlation interval in the time domain.

The problem is also solved by the claimed method of estimating the correlation interval in the frequency domain of the adopted orthogonal frequency-multiplexed symbols according to the first embodiment, which consists in the fact that:

in the groups of modulated data symbols of the second type obtained after the FFT, in which the number of modulated data symbols located between the pilot symbols N _f is assigned the minimum value N _f = N _{f min} , at the beginning and end, sequences consisting of Z zero symbols are deleted,

interpolating the pilot symbols at the points of the modulated data symbols, thereby forming a sequence of pilot symbols consisting of the received and interpolated pilot symbols,

calculate the cyclic correlation function of the generated sequence of pilot symbols,

calculating a module of the obtained cyclic correlation function of the pilot symbol sequence,

determine the extrema of the module of the obtained correlation function of the sequence of pilot symbols and compare them with a threshold,

extrema are selected that exceed a predetermined threshold, and the distances between them are determined, and then these distances are averaged, thus obtaining an estimate of the correlation interval in the frequency domain of the received orthogonal frequency multiplexed symbols.

The problem is also solved by the claimed method of estimating the magnitude of the correlation interval in the time domain of the received orthogonal frequency-multiplexed symbols according to the second embodiment, namely:

remember W groups of modulated symbols received after FFT, which contain pilot symbols and which are transmitted with a predetermined period T ₁ during a given time T ₂ when the number of modulated data symbols located between the pilot symbols in the time domain takes a minimum predetermined value N _t = N _{t min} ,

in the memorized groups of modulated symbols at the beginning and the end, the sequences consisting of Z zero characters are deleted,

form K sequences of pilot symbols, allocating for each of K sequences one pilot symbol with the same number from each of W groups of modulated symbols,

interpolating with each of the K sequences of pilot symbols at points of modulated data symbols located between them, thereby forming K sequences of pilot symbols consisting of received and interpolated pilot symbols,

calculating K cyclic correlation functions of the generated pilot symbol sequences,

calculating K modules of the obtained cyclic correlation functions of the pilot symbol sequences,

determine the extrema of each of the K modules of the obtained correlation functions of the sequences of pilot symbols and compare them with a threshold,

for each of the K modules of correlation functions, extremes are selected that exceed the threshold and average the distances between them,

average K of the obtained average distances between the extrema, thus obtaining the average value of the average distances between the extrema, which is used as an estimate of the magnitude of the correlation interval of the received orthogonal frequency-multiplexed symbols in the time domain.

The objective of the invention is also solved by the claimed devices for transmitting and receiving data in a radio communication system (options).

A data transmitting-receiving device in a radio communication system according to the first embodiment, comprising a transmitting and receiving station, wherein the transmitting station comprises a modulator, an inverse fast Fourier transform unit, a parallel-serial conversion unit, a guard interval attachment unit, a transmitter, a receiver, a splitter and an antenna, wherein the input of the modulator is the first input of the transmitting station, is the input of a sequence of binary characters, the output of the transmitter is connected to the first input of the splitter, the first the first output of which is connected to the first input of the antenna, the first output and second input of which are respectively the second input and output of the transmitting station, which generates frequency-multiplexed symbols at the output, the second output of the antenna is connected to the second input of the splitter, the second output of which is connected to the input of the receiver;

the receiving station contains an antenna, a splitter, a receiver, a transmitter, a block-parallel-parallel conversion and removal of the guard interval, a fast Fourier transform block, a channel estimator, a parallel-serial conversion block and a demodulator, wherein the first input of the antenna is the first input of the receiving station, the input frequency-multiplexed symbols, the first output of the antenna is connected to the first input of the splitter, the first output of which is connected to the input of the receiver, the output of which is connected to the first input of the serial-parallel conversion unit and removing the guard interval, the outputs of which are connected respectively to the inputs of the fast Fourier transform unit, the outputs of which are connected to the inputs of the channel estimator, the outputs of which are connected to the inputs of the parallel-serial conversion unit, the output of which is connected to the input of the demodulator, the output of which is the first output of the receiving station, forming a sequence of binary data on this output, the output of the transmitter is connected to orym input coupler, the second output of which is connected to the second input of the antenna, the second output of which is the second output of the receiving station,

according to the invention additionally introduced:

at the transmitting station, a pilot-frequency arrangement unit in the frequency domain is introduced, the first input of which is connected to the modulator output, the second input of the pilot-arrangement unit in the frequency domain is combined with the first input of the guard interval attachment unit, forming the third input of the transmitting station, which is the signal input initial installation, the third input of the block of arrangement of pilot signals in the frequency domain is connected to the output of the receiver, the outputs of the block of arrangement of pilot signals in the frequency domain are connected to the inputs of an inverse Fourier transform, the outputs of which are connected to the inputs of the parallel-serial conversion unit, the output of which is connected to the second input of the guard interval attachment unit, the output of which is connected to the transmitter input;

at the receiving station, a correlation interval estimation block in the frequency domain and a reverse channel signal generating block are introduced, while the inputs of the correlation interval estimation block in the frequency domain are connected to the outputs of the fast Fourier transform unit, the output of the correlation interval estimation block in the frequency domain is connected to the input of the signal conditioning block the return channel, the output of which is connected to the input of the transmitter, the second input of the serial-parallel conversion and removal of the guard interval is the second th input receiving station, the input signal the initial installation.

A data transmitting-receiving device in a radio communication system according to the second embodiment, comprising a transmitting and receiving station, wherein the transmitting station comprises a modulator, an inverse fast Fourier transform unit, a parallel-serial conversion unit, a guard interval attachment unit, a transmitter, a receiver, a splitter and an antenna, wherein the input of the modulator is the first input of the transmitting station, is the input of a sequence of binary characters, the output of the transmitter is connected to the first input of the splitter, the first the first output of which is connected to the first input of the antenna, the first output and second input of which are respectively the second input and output of the transmitting station, which generates frequency-multiplexed symbols at the output, the second output of the antenna is connected to the second input of the splitter, the second output of which is connected to the input of the receiver;

the receiving station contains an antenna, a splitter, a receiver, a transmitter, a block-parallel-parallel conversion and removal of the guard interval, a fast Fourier transform block, a channel estimator, a parallel-serial conversion block and a demodulator, wherein the first input of the antenna is the first input of the receiving station, the input frequency-multiplexed symbols, the first output of the antenna is connected to the first input of the splitter, the first output of which is connected to the input of the receiver, the output of which is connected to the first input of the serial-parallel conversion unit and removing the guard interval, the outputs of which are connected respectively to the inputs of the fast Fourier transform unit, the outputs of which are connected to the inputs of the channel estimator, the outputs of which are connected to the inputs of the parallel-serial conversion unit, the output of which is connected to the input of the demodulator, the output of which is the first output of the receiving station, forming a sequence of binary data on this output, the output of the transmitter is connected to orym input coupler, the second output of which is connected to the second input of the antenna, the second output of which is the second output of the receiving station,

according to the invention additionally introduced:

at the transmitting station, a pilot signal arrangement block in the time domain is introduced, the first input of which is connected to the modulator output, the second input of the pilot signal alignment block in the time domain is combined with the first input of the guard interval attachment unit, forming the third input of the transmitting station, which is the signal input initial installation, the third input of the block of the arrangement of pilot signals in the time domain is connected to the output of the receiver, the outputs of the block of the arrangement of pilot signals in the time domain are connected to the inputs an inverse Fourier transform, the outputs of which are connected to the inputs of a block parallel-to-serial conversion, the output of which is connected to the second input of the guard interval addition unit, an output connected to the input of the transmitter;

at the receiving station, a time domain correlation interval estimator and a reverse channel signal generating unit are introduced, while the inputs of the time domain correlation interval estimator are connected to the outputs of the fast Fourier transform unit, the output of the time domain correlation interval estimator is connected to the input of the signal conditioning unit the return channel, the output of which is connected to the input of the transmitter, the second input of the block of serial-parallel conversion and removal of the protective interval is orym input of the receiving station, the input signal the initial installation.

Thus, two variants of the method of transmitting and receiving data in a radio communication system are claimed. In the method of the first embodiment, the distance between the pilot symbols in the frequency domain changes, and the distance between the pilot symbols in the time domain remains fixed. In the method of the second embodiment, the distance between the pilot symbols in the time domain changes, and the distance between the pilot symbols in the frequency domain remains fixed. Each of the embodiments of the method can be applied independently of each other, and it is also possible to share them in one OFDM communication system.

The inventive device for transmitting / receiving data in a radio communication system (options) are designed respectively for implementing methods (in the frequency and time domains) and allow you to implement all the features of the claimed methods (for options).

The technical effect is achieved according to the first embodiment by introducing into the device at the transmitting station a pilot signal arrangement unit in the frequency domain and, accordingly, new connections ensuring the implementation of all the process features on the transmitting side, as well as by introducing a correlation interval estimator into the device at the receiving station in the frequency domain and the signal conditioning block of the return channel and, accordingly, new connections, ensuring the implementation of all the signs of the method on the receiving side.

The technical effect is achieved according to the second embodiment by introducing into the device at the transmitting station a pilot signal arrangement unit in the time domain and, accordingly, new connections providing all the features of the method on the transmitting side, as well as by introducing a correlation interval estimator into the device at the receiving station in the time domain and the block of the signal formation of the return channel and, accordingly, new connections, ensuring the implementation of all the features of the method on the receiving side.

To obtain a better (enhanced) effect, it is preferable to use both variants of the invention in a radio communication system, however, the separate use of each option (for the frequency or time domains) depending on the organization of the communication network is also effective and can improve the speed and quality of data transmission in the OFDM radio communication system. The decision on joint or separate use is made by the developer when planning and organizing a radio communication network.

Further, the description of the invention is illustrated by examples and drawings.

Figure 1 shows:

and - an example of the arrangement of pilot symbols;

b is an example of the time structure of orthogonal frequency multiplexed symbols.

Figure 2 is a structural diagram of a prototype device.

Figure 3 is a structural diagram of the inventive device (transmitting station) according to the first embodiment.

Figure 4 is a structural diagram of the inventive device (receiving station) according to the first embodiment.

Figure 5 is a structural diagram of the inventive device (transmitting station) according to the second embodiment.

6 is a structural diagram of the inventive device (receiving station) according to the second embodiment.

7 is a block diagram of a block for the placement of pilot signals in the frequency domain 25, is shown as an example implementation.

On Fig - structural diagram of the node of the arrangement of the pilot signals in the frequency domain 31, is shown as an example implementation.

In Fig.9 is a structural diagram of the node forming the clock pulses 32, is shown as an example implementation.

Figure 10 is a structural diagram of a control unit arrangement of the pilot signals in the frequency domain 33, shown as an example implementation.

Figure 11 is a structural diagram of a unit for attaching a protective interval 8, is shown as an example of execution

On Fig - block diagram of a block of serial-parallel conversion and removal of the guard interval 21, shown as an example implementation.

On Fig - block diagram of the block the arrangement of the pilot signals in the time domain 28, is shown as an example implementation.

On Fig is a block diagram of a control unit arrangement of the pilot symbols in the time domain 106.

On Fig made a graph diagram illustrating an algorithm for estimating the correlation interval in the frequency domain of the received orthogonal frequency-multiplexed symbols.

On Fig (a) and 16 (b) is a graph diagram illustrating an algorithm for estimating a correlation interval in the time domain of received orthogonal frequency-multiplexed symbols.

On Fig shows the signal spectrum of a single beam.

On Fig - correlation function in the frequency domain (one beam).

On Fig - signal spectrum.

On Fig and 21 - the correlation function in the frequency domain.

On Fig - correlation function in the time domain.

The device for transmitting and receiving data in a radio communication system according to the first embodiment (Figs. 3 and 4) comprises a transmitting 1 and a receiving 2 station, while the transmitting station 1 contains a modulator 4, an inverse fast Fourier transform unit 7, a connection unit for the protection interval 8, a block in parallel - serial conversion 9, transmitter 10, receiver 18, splitter 19 and antenna 20, while the input of the modulator 4 is the first input of the transmitting station 1 and is the input of a sequence of binary characters, the output of the transmitter 10 is connected to the first the splitter 19, the first output of which is connected to the first input of the antenna 20, the first output and the second input of which are respectively the second input and output of the transmitting station 1, which generates frequency-multiplexed symbols at the output, the second output of the antenna 20 is connected to the second input of the splitter 19, the second the output of which is connected to the input of the receiver 18;

the receiving station 2 contains an antenna 24, a splitter 23, a receiver 11, a transmitter 22, a block-parallel conversion and removal of the guard interval 21, a fast Fourier transform block 14, a channel estimation block 15, a parallel-serial conversion block 16 and a demodulator 17, while the first input of the antenna 24 is the first input of the receiving station 2 and the input of the frequency-multiplexed symbols, the first output of the antenna 24 is connected to the first input of the splitter 23, the first output of which is connected to the input of the receiver 11, the output One of which is connected to the first input of the serial-parallel conversion unit and removing the guard interval 21, the outputs of which are connected respectively to the inputs of the fast Fourier transform unit 14, the outputs of which are connected to the inputs of the channel estimator 15, the outputs of which are connected to the inputs of the parallel-serial conversion unit 16 the output of which is connected to the input of the demodulator 17, the output of which is the first output of the receiving station 2, forming at this output a sequence of binary data , The output of the transmitter 22 is connected to the second input coupler 23, a second output is connected to the second input of the antenna 24, which second output is the second output of the receiving station 2,

according to the invention additionally introduced:

at the transmitting station, a pilot signal arrangement unit in the frequency domain 25, the first input of which is connected to the output of the modulator 4, the second input of the pilot signal arrangement unit in the frequency domain 25 is combined with the first input of the attachment block of the guard interval 8, forming the third input of the transmitting station 1 , which is the input of the initial setup signal, the third input of the pilot signal arrangement unit in the frequency domain 25 is connected to the output of the receiver 18, the outputs of the pilot signal arrangement unit in the frequency domain 25 are connected from the input and inverse Fourier transform unit 7, which outputs are connected to inputs of a block parallel-to-serial conversion 9, whose output is connected to a second input of the addition of the guard interval 8, whose output is connected to the input of the transmitter 10;

at the receiving station 2, a correlation interval estimator in the frequency domain 26 and a reverse channel signal generating unit 27 are input, while the inputs of the correlation interval estimator in the frequency domain 26 are connected to the outputs of the fast Fourier transform unit 14, the output of the correlation interval estimator is in the frequency domain 26 connected to the input of the signal conditioning block of the return channel 27, the output of which is connected to the input of the transmitter 22, the second input of the block serial-parallel conversion and removal of the protective interval 21 is the second input of the receiving station 2, the input signal of the initial installation.

The device for transmitting and receiving data in a radio communication system according to the second embodiment (FIGS. 5 and 6) comprises a transmitting 1 and a receiving 2 station, the transmitting station comprising a modulator 4, an inverse fast Fourier transform unit 7, a parallel-serial conversion unit 9, an attachment unit guard interval 8, transmitter 10, receiver 18, splitter 19 and antenna 20, while the input of the modulator 4 is the first input of the transmitting station 1 and is the input of a sequence of binary characters, the output of the transmitter 10 is connected to the first input splitter house 19, the first output of which is connected to the first input of the antenna 20, the first output and the second input of which are respectively the second input and output of the transmitting station 1, which generates frequency-multiplexed symbols at the output, the second output of the antenna 20 is connected to the second input of the splitter 19, the second the output of which is connected to the input of the receiver 18;

the receiving station 2 contains an antenna 24, a splitter 23, a receiver 11, a transmitter 22, a block-parallel conversion and removal of the guard interval 21, a fast Fourier transform block 14, a channel estimation block 15, a parallel-serial conversion block 16 and a demodulator 17, while the first input of the antenna 24 is the first input of the receiving station 2, the input of the frequency-multiplexed symbols, the first output of the antenna 24 is connected to the first input of the splitter 23, the first output of which is connected to the input of the receiver 11, the output for which it is connected to the first input of the serial-parallel conversion unit and removing the guard interval 21, the outputs of which are connected respectively to the inputs of the fast Fourier transform unit 14, the outputs of which are connected to the inputs of the channel estimator 15, the outputs of which are connected to the inputs of the parallel-serial conversion unit 16 the output of which is connected to the input of the demodulator 17, the output of which is the first output of the receiving station 2, forming at this output a sequence of binary data, the output of the transmitter 22 is connected to the second input of the splitter 23, the second output of which is connected to the second input of the antenna 20, the second output of which is the second output of the receiving station 2,

according to the invention additionally introduced:

at the transmitting station, a pilot signal alignment block in the time domain 28 is introduced, the first input of which is connected to the output of the modulator 4, the second input of the pilot signal alignment block in the time domain 28 is combined with the first input of the guard interval 8 attachment unit, forming the third input of the transmitting station 1 , which is the input of the initial setup signal, the third input of the pilot arrangement in the time domain 28 is connected to the output of the receiver 18, the outputs of the pilot arrangement in the time domain 28 is connected s with the inputs of the inverse Fourier transform block 7, the outputs of which are connected to the inputs of the parallel-serial transform block 9, the output of which is connected to the second input of the attachment block of the guard interval 8, the output of which is connected to the input of the transmitter 10;

at the receiving station, a correlation interval estimator in the time domain 29 and a reverse channel signal generating unit 30 are input, while the inputs of the correlation interval estimator in the time domain 29 are connected to the outputs of the fast Fourier transform unit 14, the output of the correlation interval estimator in the time domain 29 is connected with the input of the signal conditioning block of the return channel 30, the output of which is connected to the input of the transmitter 22, the second input of the serial-parallel conversion block and the removal of the protective interval 21 is the second input of the receiving station 2, the input signal of the initial setup.

The block of arrangement of pilot signals in the frequency domain 25 (Fig.7) is shown as an example of execution and contains a node for the placement of pilot symbols 31, a node for generating clock pulses 32 and a node for controlling the arrangement of pilot symbols in the frequency region 33.

The node of the arrangement of pilot symbols 31 (Fig. 8) is shown as an example of execution and contains the first 34, second 35, third 36, fourth 37, fifth 38, sixth 39 logical elements AND, the first 40 and second 41 logical elements OR, the first 42, the second 43, the third 44 read-only memory devices, the first 45, the second 46, the third 47, the fourth 48, the fifth 49 registers.

The node forming the clock pulses 32 and the node forming the clock pulses 35 are made similarly, an example of implementation is shown in Fig.9. The clock generating unit comprises a first 50, a second 51, a third 52, a fourth 53, a fifth 54 and a sixth 55 logical elements AND, the first 56 and the second 57 logical elements OR, a clock generator (GTI) 58, read-only memory 59, a subtraction element 60, first 61 and second 62 counters, first 63 and second 64 triggers.

The control unit of the arrangement of pilot symbols in the frequency domain 33 (figure 10) is shown as an example of execution and contains the first 65, second 66, third 67, fourth 68 logical elements And, the first 69, second 70, third 71 and fourth 72 counters, the first 73, second 74, third 75 and fourth 76 triggers, read-only memory 77, OR gate 78, first 79, second 80 and third 81 registers, computing element 82.

The attachment block of the guard interval 8 (Fig. 11) is given as an example of execution and contains the first 83, second 84, third 85, fourth 86, fifth 87, sixth 88, seventh 89 and eighth 90 logic elements And, the first 91 and second 92 registers, the first 93, second 94 and third 95 logic gates OR, clock generator (GTI) 96, counter 97 and trigger 98.

Block serial-parallel conversion and removal of the guard interval 21 (Fig) is shown as an example of execution and contains a register 99, a clock generator (GTI) 100, a counter 101, a trigger 102 and a logical element AND 103.

The block of the arrangement of pilot signals in the time domain 28 (Fig.13) is shown as an example of execution and contains a node for the placement of pilot symbols 104, a node for generating clock pulses 105 and a node for controlling the arrangement of pilot symbols in the frequency domain 106.

The control unit of the arrangement of pilot symbols in the time domain 106 (Fig) is shown as an example of execution and contains the first 107, second 108, third 109, fourth 110, fifth 111 and sixth 112 logic elements And, the first 113, second 114, third 115 , fourth 116 and fifth 117 counters, first 118, second 119, third 120 and fourth 121 triggers, first 122, second 123 and third 124 read-only memory devices, first 125, second 126 and third 127 logical elements OR, first 128 and second 129 registers, logical element NOT 130.

The inventive method of transmitting and receiving data in a radio communication system according to the first embodiment is carried out on a device whose structural diagram is made in FIGS. 3 and 4.

At the transmitting station 1 (Fig. 3), a sequence of binary characters is received, which from the first input of the transmitting station 1 is fed to the input of the modulator 4. In the modulator 4, the sequence is divided into words consisting of d characters (d = 1, 2, ..., G) Each word is assigned a modulated data symbol in the form of a complex number. From the output of the modulator 4, the signal is fed to the first input of the block of arrangement of pilot signals in the frequency domain 25, the second input of which receives the signal of the initial installation (NU).

In the block of arrangement of pilot signals in the frequency domain 25, the sequence of modulated data symbols is converted into parallel groups of two types, the first of which consists of Q1 modulated data symbols, where Q1 is a given number, the second is from Q2 modulated data symbols, where Q2 is a given number . The groups of the first kind are supplemented with sequences consisting of Z zero characters, placing them at the beginning and end of the group, with Q1 + 2Z = N. Groups of the second type are supplemented with sequences consisting of Z null characters, positioning them at the beginning and end of the group, and every N _f modulated data symbols have a pilot symbol, where N _f = Q2 / K, with Q2 being a multiple of K and Q2 + 2Z + K = N, and K is the number of pilot symbols in the group of the second type.

A sequence of groups of the first and second types is formed in such a way that groups of the second type follow every N _t groups of the first type, where N _t is a given number. Moreover, in groups of the second type, spaced apart by a given number V of groups of this type, the number of modulated data symbols N _f located between the pilot symbols is assigned the minimum specified value N _f = N _{f min} .

The output signals from block 25 are fed to the inputs of the inverse fast Fourier transform (OBPF) block 7. In block 7, each group performs an inverse fast Fourier transform, forming parallel output groups of values of the inverse fast Fourier transform (OBPF), which from the output of block 7 go to the inputs of the block parallel-serial conversion 9.

In the parallel-serial conversion unit 9, parallel output groups of IFFT values are converted into serial form, thereby forming a sequence of transmitted symbols, each of which contains N received IFFT values, which from the output of block 9 are input to the attachment block of the guard interval 8.

In the block of attachment of the guard interval 8, each transmitted symbol is supplemented with a guard interval, thereby forming a sequence of orthogonal frequency-multiplexed symbols.

Frequency-multiplexed symbols from the output of block 8 are fed to the input of the transmitter 10. The output signal of the transmitter 10 through the splitter 19 is fed to the antenna 20.

At the receiving station 2 (figure 4), the signal from the antenna 24 through the splitter 23 is fed to the input of the receiver 11.

In the receiver 11 perform amplification, frequency selection, frequency signal conversion, frequency and time synchronization. From the output of the receiver 11, the frequency-multiplexed symbols are fed to the first input of the serial-parallel conversion block and the removal of the guard interval 21, the second input of which receives the initial setting signal (NU).

In the block of parallel-parallel conversion and removal of the guard interval 21, the guard interval is removed, thereby forming a sequence of received symbols, and the received symbols are converted into parallel groups of input values, which from the outputs of block 21 go to the inputs of the fast Fourier transform block 14 (FFT).

With each group of input values in block 14, a fast Fourier transform (FFT) is performed, thus forming N modulated symbols in each group.

The output values of the FFT block 14 from its outputs go to the inputs of the channel estimator 15 and the inputs of the correlation interval estimator in the frequency domain 26.

In the block for estimating the correlation interval in the frequency domain 26 according to the pilot symbols of the second type of groups in which the number of modulated data symbols located between the pilot symbols N _f is assigned the minimum value N _f = N _{f min} , the correlation interval of the received modulated symbols in the frequency domain N _fcor normalized to the frequency offset between the OFDM symbol subcarriers. The estimate of the correlation interval of the received modulated symbols in the frequency domain is received from the output of block 26 to the input of the signal conditioning block of the return channel 27. In block 27, the estimate of the correlation interval of the received modulated symbols in the frequency domain is converted to frequency-multiplexed symbols that are received from the output of block 27 to the input the transmitter 22. The output signal of the transmitter 22 through the splitter 23 enters the antenna 24. Thus, the received estimate of the duration of the correlation interval in the frequency domain is transmitted to and the transmitting station 1.

In the channel estimator 15 in each group, the pilot channel is evaluated by the pilot symbols. Using the obtained results of the evaluation of the communication channel, an evaluation of the modulated data symbols is performed, forming groups of estimates of the modulated data symbols, which are output from the outputs of block 15 to the inputs of the block of parallel-serial conversion 16.

In the parallel-serial conversion unit 16, the groups of estimates of the modulated data symbols are converted into serial form, thereby forming a sequence of estimates of the modulated data symbols, which are output from the output of the block 16 to the input of the demodulator 17.

In the demodulator 17, demodulation of the obtained estimates of the modulated data symbols is performed, thereby forming a sequence of binary data, which from the output of the demodulator 17 is fed to the first output of the receiving station 2.

At transmitting station 1, in the block of arrangement of pilot signals in the frequency domain 25, the value of N _{f is} adjusted so that the condition N _f ≤N _{f cor is} satisfied, where N _f is the number of modulated data symbols located between the pilot symbols, and N _fcor - Estimation of the duration of the correlation interval in the frequency domain.

The initial setup signal, as a rule, is introduced into all the devices of the receiving and transmitting stations. However, this signal is not essential for the operation of the device and therefore it is indicated only on electrical circuits, and on a structural diagram this signal is not indicated. However, for a better understanding of the operation of the device, such a signal is indicated on the given structural diagrams.

The inventive method of transmitting and receiving data in a radio communication system according to the second embodiment is carried out on a device whose structural diagram is made in FIG. 5 (transmitting station) and 6 (receiving station).

At the transmitting station 1 (Fig. 5), a sequence of binary symbols is received. From the first input of the transmitting station, a sequence of binary characters is fed to the input of modulator 4.

In modulator 4, the sequence is divided into words consisting of d characters (d = 1, 2, ..., D). Each word is assigned a modulated data symbol in the form of a complex number. The output signal of the modulator 4 is supplied to the first input of the block of the arrangement of the pilot signals in the time domain 28.

In the block of arrangement of pilot signals in the time domain 28, the sequence of modulated data symbols is converted into parallel groups of two types, the first of which consists of Q1 modulated data symbols, where Q1 is a given number, the second is from Q2 modulated data symbols, where Q2 is a given number . The groups of the first kind are supplemented with sequences consisting of Z zero characters, placing them at the beginning and end of the group, with Q1 + 2Z = N. Groups of the second type are supplemented with sequences consisting of Z null characters, positioning them at the beginning and end of the group, and every N _f modulated data symbols have a pilot symbol, where N _f = Q2 / K, with Q2 being a multiple of K and Q2 + 2Z + K = N, and K is the number of pilot symbols in the group of the second type.

A sequence of groups of the first and second types is formed in such a way that groups of the second type follow every N _t groups of the first type, where N _t is the given number of modulated data symbols located between the pilot symbols in the time domain. Moreover, with a given period T ₁ for a given time T ₂ assign the number of modulated data symbols located between the pilot symbols in the time domain, the minimum specified value N _t = N _{t min} . The output signals from block 28 are fed to the inputs of the block inverse fast Fourier transform (OBPF) 7.

In block 7, an inverse fast Fourier transform (IFFT) is performed with each group, forming parallel output groups of inverse fast Fourier transform (OBFF) values. The output signals from block 7 are fed to the inputs of the block parallel-serial conversion 9.

In the parallel-serial conversion unit 9, the parallel output groups of IFFT values are converted into a serial form, thereby forming a sequence of transmitted symbols, each of which contains N received IFFT values, which from the output of block 9 go to the second input of the attachment block of the guard interval 8, to the second the input of which is the initial installation signal (NU).

In the block of attachment of the guard interval 8, each transmitted symbol is supplemented with a guard interval, thereby forming a sequence of orthogonal frequency-multiplexed symbols, which from the output of block 8 go to the input of the transmitter 10.

The output signal of the transmitter 10 through the splitter 19 enters the antenna 20.

At the receiving station 2 (Fig.6), the signal from the antenna 24 through the splitter 23 is fed to the input of the receiver 11.

The receiver 11 performs amplification, frequency selection, frequency signal conversion, frequency and time synchronization. From the output of the receiver 11, the frequency-multiplexed symbols are fed to the first input of the serial-parallel conversion block and the removal of the guard interval 21, the second input of which receives the initial setting signal (NU).

In the series-parallel conversion and deletion block of the guard interval 21, the guard interval is removed, thereby forming a sequence of received symbols, and the received symbols are converted into parallel groups of input values. The output signals from block 21 are fed to the inputs of the fast Fourier transform (FFT) block 14.

In block 14, a fast Fourier transform (FFT) is performed with each group of input values, thus forming N modulated symbols in each group.

The output values of the FFT block come from its outputs to the inputs of the channel estimator 15 and the correlation interval estimator in the time domain 29.

In the block for estimating the correlation interval in the time domain 29 according to the pilot symbols of the second kind of groups that are transmitted with a predetermined period T ₁ during a predetermined time T ₂ , when the number of modulated data symbols located between the pilot symbols in the time domain takes a minimum predetermined value N _t = N _{t min} , estimate the duration of the correlation interval in the time domain N _tcor normalized to the duration of the orthogonal frequency-multiplexed symbols received modulated symbols.

The estimate of the correlation interval of the received modulated symbols in the time domain from the output of block 29 is input to the signal conditioning unit of the return channel 30. In this block, the estimate of the correlation interval of the received modulated symbols in the frequency domain is converted into frequency-multiplexed symbols, which are transmitted to the transmitter from the output of block 30 22.

The output signal of the transmitter 22 through the splitter 23 enters the antenna 24.

Thus, the obtained estimate of the duration of the correlation interval in the time domain is transmitted to the transmitting station 1.

In the channel estimator 15 in each group, the pilot channel is evaluated by the pilot symbols. Using the obtained results of the evaluation of the communication channel, an evaluation of the modulated data symbols is performed, forming groups of estimates of the modulated data symbols, which are output from the outputs of block 15 to the inputs of the block of parallel-serial conversion 16.

In the parallel-serial conversion unit 16, the groups of estimates of the modulated data symbols are converted into serial form, thereby forming a sequence of estimates of the modulated data symbols, which are output from the output of the block 16 to the input of the demodulator 17.

In the demodulator 17, demodulation of the obtained estimates of the modulated data symbols is performed, thereby forming a sequence of binary data, which, from the output of the demodulator, goes to the first output of the receiving station 2.

At the transmitting station 1 in the block of arrangement of pilot signals in the time domain 28, the value of N _{t is} adjusted so that the condition N _t ≤N _{tcor is satisfied} , where N _t is the number of modulated data symbols located between the pilot symbols in the time domain, N _tcor - the duration of the correlation interval in the time domain.

The initial installation signal (NU), as a rule, is introduced into all devices of receiving and transmitting stations. However, this signal is not essential for the operation of the device and therefore it is indicated only on electrical circuits, and on a structural diagram this signal is not indicated. However, for a better understanding of the operation of the device, such a signal is indicated on the given structural diagrams.

To implement the proposed method of data transmission-reception in a radio communication system, it is necessary to evaluate the value of the correlation interval, which can be performed in various ways.

The inventive methods for estimating the correlation interval of the received orthogonal frequency-multiplexed symbols (for the frequency or time domains - options) are developed respectively for the options for implementing the method of transmitting and receiving data in a radio communication system.

Consider the procedure for estimating the correlation interval of received orthogonal frequency-multiplexed symbols according to the first embodiment in the frequency domain, with reference to Fig. 15, which illustrates this procedure.

In the groups of modulated data symbols of the second type obtained after the FFT, in which the number of modulated data symbols located between the pilot symbols N _f is assigned the minimum value N _f = N _{f min} , sequences consisting of Z zero symbols are deleted at the beginning and end.

Pilot symbols are interpolated at points of modulated data symbols, thereby forming a pilot symbol sequence consisting of received and interpolated pilot symbols. Interpolation can be performed in various ways. For example, the methods described in the books: V.I. Tikhonov. Statistical radio engineering. Moscow: Radio and Communications, 1982 (p. 606) or L.I. Turchak. Fundamentals of numerical methods. Moscow: Science, 1987 (p. 49).

The cyclic correlation function of the generated pilot symbol sequence is calculated.

The module of the obtained cyclic correlation function of the pilot symbol sequence is calculated.

The extrema of the module of the obtained correlation function of the pilot symbol sequence are determined and compared with a threshold.

Extrema that exceed a given threshold is distinguished and the distances between them are determined, and then these distances are averaged, thus obtaining an estimate of the correlation interval in the frequency domain of the received orthogonal frequency multiplexed symbols.

The extremes can be determined in various ways, for example, by the methods described in the book of L.I. Turchak. Fundamentals of numerical methods. Moscow: Science, 1987 (p. 172).

On Fig shows the signal spectrum of the reverse channel according to the standard 802.16, obtained by modeling, with the following parameters: FFT-1024 size, signal band = 10 MHz, the duration of the OFDM symbol with a guard interval Ts = 100.8 μs, the type of modulation is quadrature-amplitude 16 position modulation (16-QAM), the transmitted information consists of one "zero bits".

On Fig shows the cyclic correlation function of the signal in the frequency domain.

These figures show that the signal spectrum without fading is uniform, and the correlation function is smooth with one maximum.

Figure 19 shows a spectrum of a three-beam signal. The delays of the second and third rays normalized to a sampling period of 88 nanoseconds are 45 and 97. The normalized powers of the second and third rays relative to the first (in decibels) are -4db and -6db. The frequency of fading is 500 Hz.

Figure 20 shows the cyclic correlation function of a three-beam signal in the frequency domain.

On Fig and 20 it is seen that the signal spectrum during fading is uneven and periodic and the correlation function is also uneven and periodic.

On Fig shows the cyclic correlation function of a three-beam signal in the frequency domain in the range from 400 to 500 samples. This figure shows that the average distance between the extrema that exceeded the threshold is approximately equal to 20-30 sampling periods.

In practice, it is easiest to implement a method for estimating the correlation interval in the frequency domain of received orthogonal frequency-multiplexed symbols on a microprocessor according to a graph diagram illustrating the algorithm of the method in FIG.

Consider a procedure for estimating a correlation interval of received orthogonal frequency-multiplexed symbols according to the second embodiment, in the time domain, with reference to FIGS. 16a and 16b, which illustrate this procedure.

The method of estimating the correlation interval of the received orthogonal frequency-multiplexed symbols in the time domain is as follows.

W groups of modulated symbols received after the FFT are stored, which contain pilot symbols and which are transmitted with a predetermined period T ₁ during a given time T ₂ , when the number of modulated data symbols located between the pilot symbols in the time domain takes a minimum predetermined value N _t = N _{t min} .

In stored groups of modulated symbols, sequences consisting of Z zero characters are deleted at the beginning and end.

K sequences are formed, selecting one pilot symbol with the same number from each of W modulated symbol blocks.

Interpolation is performed with each of the K sequences of pilot symbols at points of modulated data symbols located between them, thereby forming K sequences of pilot symbols consisting of the received and interpolated pilot symbols. Interpolation can be performed in various ways, for example, the methods described in the books: V.I. Tikhonov. Statistical radio engineering. Moscow: Radio and Communications, 1982 (p. 606) and L.I. Turchak. Fundamentals of numerical methods. Moscow: Science, 1987 (p. 49).

To calculate the cyclic correlation functions of the generated sequences of pilot symbols.

K modules of the obtained cyclic correlation functions of pilot symbol sequences are calculated.

The extrema of each of the K modules of the obtained correlation functions of the pilot symbol sequences are determined and compared with a threshold. The determination of extrema can be performed in various ways, for example, by the method described in the book of L.I. Turchak. Fundamentals of numerical methods. Moscow: Science, 1987 (p. 172).

For each of the K modules of correlation functions, extrema that exceed the threshold are distinguished and the distances between them are averaged.

The obtained average distances between the extrema are averaged K, thus obtaining the average value of the average distances between the extrema, which is used as an estimate of the value of the correlation interval of the received orthogonal frequency-multiplexed symbols in the time domain.

On Fig shows the cyclic correlation function of the three-beam signal of the reverse channel according to the standard 802.16 in the time domain. The delays of the second and third rays normalized to a sampling period of 88 nanoseconds are 45 and 97. The normalized powers of the second and third rays relative to the first (in decibels) are -4db and -6db. The frequency of fading is 1000 Hz.

This figure shows that the average distance between the extrema that exceeded the threshold is approximately equal to five durations of the frequency-multiplexed symbol.

In practice, it is easiest to implement a method for estimating the correlation interval of received orthogonal frequency-multiplexed symbols in the time domain on a microprocessor according to the algorithm illustrated in FIGS. 16a and 16b.

For a better understanding of the implementation of the proposed method for transmitting and receiving data in a radio communication system (options), as well as the operation of the device for its implementation (options), we next consider examples of the execution of blocks included in the transmitting and receiving stations of the claimed device.

Block parallel-serial conversion 9 can be performed in the form of parallel-serial register. Modulated characters are written in the parallel register, and are read sequentially.

The channel estimator 15 may be implemented in various ways. For example, channel estimation by pilot symbols may be performed as described in articles [Michele Morelli and Umberto Mengali. A comparison of pilot-aided channel estimation methods for OFDM systems. IEEE transactions on signal processing, vol. 49, no.12, December 2001] and [Sinem Coleri, Mustafa Ergen, Anuj Puri and Ahmad Bahai. Channel estimation techniques based on pilot arrangement in OFDM systems. IEEE transactions on broadcasting, vol. 48, no.3, September 2002]. It is easiest to implement the above procedure for channel estimation by pilot symbols on a microprocessor.

Examples of the execution of the FFT 14 and OBPF 7 block are given in the book "Digital Filters and Signal Processing Devices on Integrated Circuits". Ed. B.F. Vysotsky, M .: Radio and communications, 1984, p. 103 and in the patent of the Russian Federation No.2012051 "Device for fast Fourier transform", IPC ⁵ G 06 F 15/352 (publication date - 1994.04.30). The FFT block 7 can also be implemented on the basis of a signal microprocessor (for example, from the TMS320 series) or a microprocessor for fast Fourier transform of 1815VF3.

Figure 7 shows, as an example of implementation, a structural diagram of a block for arranging pilot signals in the frequency domain 25.

Block arrangement of pilot signals in the frequency domain operates as follows.

The input modulated symbols are sequentially fed to the input of the block of arrangement of pilot signals and adjust the shift between them in the frequency domain and then to the input of the node of arrangement of pilot symbols 31, in which, according to the control signals, the first write signal (Zap 1), the second recording signal (Zap 2 ), settings of the pilot symbol (PS) and the arrangement of data symbols (Sim Data) of the pilot symbol arrangement control unit in the frequency domain 33 transform the sequence of modulated data symbols into parallel groups of two types, the first of which x consists of Q1 modulated data symbols, where Q1 is a given number, the second is from Q2 modulated data symbols, where Q2 is a given number. Groups of the first kind are supplemented with sequences consisting of Z zero characters (zeros), placing them at the beginning and end of the group, with Q1 + 2Z = N. Groups of the second type are supplemented with sequences consisting of Z null characters, positioning them at the beginning and end of the group, and every N _f modulated data symbols have a pilot symbol, where N _f = Q2 / K, with Q2 being a multiple of K and Q2 + 2Z + K = N, and K is the number of pilot symbols in the group of the second type. A sequence of groups of the first and second types is formed in such a way that groups of the second type follow every N _t groups of the first type, where N _t is a given number. Moreover, in groups of the second type, spaced apart by a given number V of groups of this type, the number of modulated data symbols N _f located between the pilot symbols is assigned the minimum specified value N _f = N _{f min} . After receiving from the output of the receiver 18 to the third input of the block of arrangement of pilot signals in the frequency domain 25 estimates the duration of the correlation interval in the frequency domain N _fcor adjust the value of N _f so that the condition N _f ≤N _{f cor is} satisfied.

The clock shaping unit 32 generates clock pulses for the pilot symbol arrangement unit 31 and the pilot symbol arrangement control unit in the frequency domain 33.

The node placement of the pilot symbols 31 (Fig) works as follows.

The input modulated symbols through the fifth logical element AND 38 are sequentially recorded in the fourth shift register 48. After filling the modulated symbols of the fourth shift register 48, the input modulated symbols through the sixth logical element And 39 are sequentially written in the fifth shift register 49. In this case, the modulated symbols recorded in the fourth the shift register 48, are read from this register through the third logical element AND 36. The read speed is greater than the write speed. After filling the fifth shift register 49, the input modulated symbols through the fifth logical element AND 38 are sequentially written to the fourth shift register 48. In this case, the modulated symbols recorded in the fifth shift register 49 are read from this register through the fourth logical element And 37. Thus, the fourth 48 and fifth 49 shift registers read and write modulated input symbols alternately. The operation of the registers 48 and 49 is provided by control signals: the first recording signal (Zap 1) and the second recording signal (Zap 2) coming from the control unit for the arrangement of pilot symbols in the frequency domain 33, and the first clock pulses (TI1) and second clock pulses ( TI2) coming from the node forming the clock pulses 32.

Modulated symbols from the output of the third logical element AND 36 or the fourth logical element AND 37 through the second logical element OR 41, the second logical element AND 35 and the first logical element OR 40 are input to the second serial-parallel register 46. The modulated symbols are written in the second register 46 sequentially, and come from its outputs to the outputs of the node placement of the pilot symbols 31 in parallel. At the same time, the group of modulated symbols recorded in the second register 46 is supplemented with sequences consisting of Z zero characters (zeros), placing them at the beginning and end of the group. To do this, in the first 45 and third 47 parallel registers from the second 43 and third 44 ROM write zero characters (zeros). Thus, from the outputs of the first 45, second 46, and third 47 registers, N modulated symbols are simultaneously sent to the outputs of the pilot symbol arrangement node. Of these, 2Z characters are zero.

The control signals of the installation of the pilot signal (PS) and the arrangement of data symbols (Sim Dan) from the control unit of the arrangement of pilot symbols in the frequency domain 33, convert the sequence of modulated data symbols received sequentially to the input of the second serial-parallel register 46, parallel groups of two kinds.

Groups of the first kind consist of N-2Z data characters and 2Z null characters.

In the group of the second type, every N _f modulated data symbols put a pilot symbol coming from the first ROM 42.

The control signals the installation of the pilot signal and the arrangement of data symbols also form a sequence of groups of the first and second types in such a way that groups of the second type followed every N _t groups of the first type, where N _t is a given number. Moreover, in groups of the second type, spaced apart by a given number V of groups of this type, the number of modulated data symbols N _f located between the pilot symbols is assigned the minimum specified value N _f = N _{f min} .

The structural diagram of the node forming the clock pulses is shown in Fig.9.

The node forming a clock pulse 32 operates as follows.

According to the control signals, the first recording signal (Zap 1) and the second recording signal (Zap 2), coming from the control unit for arranging pilot symbols in the frequency domain 33, from clock pulses of input symbols and clock pulses of signal processing (clock pulses of input symbols are larger than clock signal processing pulses) of a clock pulse generator (GTI) form the first clock pulses (TI1) and second clock pulses (TI2) for the pilot signal arrangement unit.

The clock pulses of the input symbols through the first logical element And 50 or through the fourth logical element And 53 (at the input of which there is either a first write signal or a second write signal) and then either through the first logical element OR 56, or through the second logical element OR 57 to the output of node 32.

The number of modulated data symbols in one group of modulated symbols Q is recorded in the first counter 61 by the control signal of the pilot symbol arrangement unit in the frequency domain (Sync Zap) from the pilot symbol arrangement control node in the frequency domain 33. For groups of the first kind Q = Q1, and for groups of the second kind, Q = Q2. The signal from the first counter 61 sets the first trigger 63 to a state in which the clock signal processing through the fifth logical element And 54 are fed to the inputs of the second 51 and third 52 logic elements I. Then the clock pulse of the signal processing through one of these logic elements (at the input which is present either the first recording signal or the second recording signal) and then either through the first logical element OR 56, or through the second logical element OR 57 go to the output of the node 32.

The clock pulses of the signal processing also go to the input of the first counter 61. The counter works on subtraction. After the input of the counter Q of the clock signal processing pulses, this counter generates a control signal, which sets the first trigger 63 to a state in which the clock signal processing pulses are not output to the fifth logical element And 54.

Thus, both the first clock pulses and the second clock pulses arrive at the outputs of the node 32 in the form of two sequences, the first of which consists of clock pulses of the signal processing, and the second of the clock pulses of the input symbols and in each of which the number of pulses is equal to the number modulated data symbols in one group.

The clock pulses of the input symbols also go to the output of the node, as the input clock pulses (TI In).

The number of modulated data symbols in one group of modulated Q symbols also arrives at the first input of the subtraction element 60. The number of modulated data symbols in one group of the first type Q1 is received at the second input of the subtraction element 60 from the output of the ROM 58. From the output of the subtraction element 60, the difference Q1-Q is supplied to the first input of the second counter 62 and is written to this counter by the write synchronization control signal. Obviously, for groups of the first kind, this difference is zero. The second counter 62 operates on a subtraction. After a pulse is received at the input of the counter Q1-Q from the output of the second counter 62, a signal is sent to the second trigger 64, which sets it into a state in which the output signal of the fifth logical element And 54 passes through the sixth element And 55 to the output of node 32. This signal is denoted as shift clock pulses (TI Sdv).

Thus, the shift clock pulses arrive at the node output by non-overlapping sequences in each of which the number of pulses is equal to the number of modulated data symbols in one Q group.

The control signal of the initial installation (NU) sets the first 61 and second 62 counters, the first 63 and second 64 flip-flops and the clock generator 58 to the initial state.

The block diagram of the control unit arrangement of the pilot symbols in the frequency domain 33 is shown in Fig.10.

The control unit of the arrangement of pilot symbols in the frequency domain 33 operates as follows.

The duration of the control signals generated by the control unit arrangement of the pilot symbols in the frequency domain, and their time shifts relative to each other are determined by four counters. The first counter 69 determines the duration of the control signals of the placement of the data symbols and set the pilot signals. The second counter 70 determines the number of groups of the first type N _t between groups of the second type. The third counter 71 determines the duration of the control signals — the first recording signal and the second recording signal. The fourth counter 72 determines the number of groups of the first and second kind between groups of the second kind, in which N _f = N _fmin .

The control signal of the initial installation through the third logical element And 67 sets the fourth trigger 76 so that from its output the control signal to the second logical element And 66. In this case, with the ROM 77 through the second logical element And 66 and the logical element OR 78 in the first register 79, the minimum number of modulated data symbols located between the pilot symbols N _{fmin is recorded} , which is then overwritten in the first counter 69.

The control signal of the initial installation also sets the first trigger 73 in such a way that from its first output a control signal for the arrangement of data characters (Sim Dan) is received.

The control signal of the initial installation also sets the second trigger 74 in such a way that from its output a control signal is supplied to the first logical element And 65. In this case, the clock pulses of the shift through the first logical element And 65 are fed to the input of the first counter 69, which after the receipt of N _fmin clock shear pulses (the counter operates in the subtraction mode) generates at the first output a control signal supplied to the first trigger 73. By this control signal, the first trigger 73 goes into a state in which from the second the output receives the control signal for setting the pilot signal (PS), and the first output does not receive the control signal for the arrangement of data symbols. The control signal installation of the pilot signal is supplied to the output of the node 33 and to the first counter 69, in which N _{f min is} written using this control signal. After the receipt of N _fmin +1 clock pulse, the first counter 69 controls the signal from the second output and sets the first trigger 73 in a state in which from its first output the node receives a control signal for the arrangement of data symbols and the second output does not receive a control signal signal. Thus, the first trigger 73 switches K times, where K is the number of pilot symbols in the group of modulated symbols.

The number of modulated data symbols located between the pilot symbols N _f , from the output of the first register 79 also goes to the computing element 82 of the number of modulated data symbols in one group Q. Moreover, for groups of the first kind, Q = Q1, where Q1 is a given number, and for the second of the form Q = Q2 and is calculated by the formula Q2 = (N-2Z) / (1+ (1 / N _f )). This formula can be easily obtained from the expressions Q2 + 2Z + K = N and N _f = Q2 / K. From the output of the computing element 82, the number of modulated data symbols in one group Q through the second register 80 is recorded in the third counter 71 and is output to the node.

The input of the third counter 71 receives input clock pulses. After Q input clock pulses (the counter operates in the subtraction mode), the third counter 71 generates a control signal supplied to the third trigger 75. By this control signal, the third trigger 75 switches to the opposite state, in which its output control signals are the first write signal (Rec 1 ) and the second recording signal (Zap 2) change their values to the opposite. Control signals - the first recording signal and the second recording signal are supplied to the corresponding outputs of the node 33.

The control output of the third counter 71 also writes to this counter the number of modulated data symbols in one Q group.

The control signal output of the third counter 71 also enters the fourth trigger 76, which is set so that from its first output a control signal is supplied to the fourth logical element And 68. In this case, from the third register 81 through the fourth logical element And 68 and the logical element OR 78 the first register 79 records the number of modulated data symbols located between the pilot symbols N _f , which is then overwritten in the first counter.

The number of modulated data symbols located between the pilot symbols, N _f from the output of the first register 79, is sent to the calculation element 82 of the number of modulated data symbols in one group Q. From the output of the calculation element 82 of the number of modulated data symbols in one group, the signal is supplied through the second register 80 the output of the node 33 and is recorded in the third counter 71.

The output control signal from the third counter 71 also goes to the output of the node 33 as a write synchronization control signal (Sync Zap) and to the input of the second counter 70. When the first control signal from the third counter 71 arrives at the input of the second counter 70 from the second output of the second counter 70 to second flip-flop 74 receives a control signal that sets it in such a way that its one output control signal to the first AND gate 65. When N _t output signals of the third counter 71 output of the second counter 70 on dulls to the second trigger 74 and sets it in such a way that a control signal is sent to its first logic element And 65 from its output. In this case, the shift clock pulses are fed to the input of the first counter 69. Next, the process of generating output control signals by arranging data symbols and setting the pilot signal repeats.

After receiving from the third counter 71 N _t +1 output signals from the second output of the second counter 70, the output signal is supplied to the second trigger 74 and sets it in such a way that the control signal to the first logical element And 65 is removed from its output.

The input clock pulses also arrive at the fourth counter 72, which, after the number of pulses equal to the product Q * N _t * V of the input clock pulses, generates a control signal that, through the third logic element And 67, sets the fourth trigger 76 in such a way that from its output the control signal to the second logical element And 66. In this case, with the ROM 77 through the second logical element And 66 and the logical element OR 78 in the first register 79 recorded the minimum number of modulated data symbols located between the pilot bounded by N _fmin .

Thus, the control unit of the arrangement of pilot symbols in the frequency domain generates the following continuously overlapping control signals - the first recording signal (Rec 1) and the second recording signal (Rec 2). The duration of these signals is equal to the duration of the modulated data symbols of one group.

The control unit 33 also generates control signals for the placement of data symbols (Sim Dan) and the installation of the pilot signal (MS). The duration of the data symbol _spread signal is equal to the duration of N _fmin or N _f modulated data symbols. The duration of the pilot setting signal is equal to the duration of one modulated data symbol. A pair of control signals for the arrangement of data symbols and the installation of the pilot signal follows continuously one after another K times, where K is the number of pilot symbols in the group. To pairs of control signals — the arrangement of data symbols and the installation of pilot signals are separated from each other by a duration of N _t groups of modulated symbols.

The control unit 33 also generates the number of modulated data symbols in one group Q and a write synchronization control signal (Sync Zap), which determines the time when the number of modulated data symbols in the group arrives at the output of the control node.

The attachment operation of the guard interval is illustrated in FIG. 1b. In this figure, the time period corresponding to the guard interval is indicated as T _g , and the transmitted symbol is T _N. For example, for 802.16, the guard interval is T _g = 11.2 μs (128 samples), and the duration of the transmitted symbol is T _N = 89.6 μs (1024 samples). On fig.1b shows that the attachment of the guard interval is that after IFFT and parallel-serial conversion of the last G of N samples of the transmitted symbol is repeated at the beginning of this symbol. Thus, the orthogonal frequency-multiplexed symbol consists of G + N samples.

The block connecting the protective interval 8 can, for example, be implemented according to the structural diagram shown in Fig.11.

The input samples of the transmitted symbol alternately through the first 83 or second 84 logical elements AND are sequentially written respectively in the first 91 or second 92 registers. Then, the recorded samples of the transmitted symbol alternately through the third 85 or fourth 86 logical elements AND and the first logical element OR 93 are fed to the output of block 8. That is, if the samples are written in the first register 91, then they are read from the second register 92 and vice versa, if in the second register 92 write samples, then from the first register 91 read. The read rate is greater than the write frequency. Moreover, after writing to the register of samples of one transmitted symbol, the last G of N samples are written in the register at the beginning of this symbol.

Using the counter 97, trigger 98, fifth 87, sixth 88, seventh 89 and eighth 90 logic gates AND, second 94 and third 95 logic gates OR, clock pulses and control signals for the first 83, second 84 are formed from clock pulses of the clock pulse generator 96 , the third 85 and the fourth 86 logical elements AND and the first logical element OR 93. In this case, the counter 97 determines the duration of the interval of recording samples of the transmitted symbol in the register. The initial setup control signal performs the initial setup of the clock 96, counter 97, and trigger 98.

Block serial-parallel conversion and removal of the guard interval 21 can, for example, be implemented according to the structural diagram shown in Fig.12.

The samples of the orthogonal frequency-multiplexed symbols are sequentially input to the block of serial-parallel conversion and removal of the guard interval 21. Each of these symbols contains G + N samples. In the block, the samples are sequentially recorded in a serial-parallel register 99. Of the 99 G + N samples received at the input of the register of one frequency-multiplexed symbol, only N samples are recorded in the register itself. The guard interval samples are not written to register 99. From the register 99 N samples in parallel arrive at the output of block 21.

Counter 101 determines the duration of the received symbol and the duration of the guard interval. The logic element And 103, the trigger 102 and the counter 101 of the clock pulses of the clock generator 100 generate clock pulses for the register 99.

The signal conditioning unit of the return channel 27 can be implemented in various ways. For example, since the transmitting part in the prototype (from the modulator to the transmitter) is completed.

On Fig made, as an example of implementation, the structural diagram of the block the arrangement of the pilot signals in the time domain 28.

The arrangement of the pilot signals in the time domain 28 operates as follows.

The input modulated symbols are sequentially fed to the input of the block of arrangement of pilot signals in the time domain 28 and then to the input of the node of arrangement of pilot symbols 104, in which, according to the control signals, the first recording signal (Zap 1), the second recording signal (Zap 2), setting the pilot -symbol (PS) and data symbol arrangement (Sim Dan) of the pilot symbol arrangement control unit in the time domain 106 transform a sequence of modulated data symbols into parallel groups of two types, the first of which consists of Q1 modulated The letters data where Q1 - a predetermined number, the second one - of the modulated data symbols Q2, where Q2 - a predetermined number. Groups of the first kind are supplemented with sequences consisting of Z zero characters (zeros), placing them at the beginning and end of the group, with Q1 + 2Z = N. Groups of the second type are supplemented with sequences consisting of Z null characters, positioning them at the beginning and end of the group, and every N _f modulated data symbols have a pilot symbol, where N _f = Q2 / K, with Q2 being a multiple of K and Q2 + 2Z + K = N, and K is the number of pilot symbols in the group of the second type.

A sequence of groups of the first and second types is formed in such a way that groups of the second type follow every N _t groups of the first type, where N _t is the number of modulated data symbols located between the pilot symbols in the time domain. Moreover, with a given period T ₁ during a given time T ₂ assign the number of modulated data symbols located between the pilot symbols in the time domain, the minimum specified value N _t = N _tmin. .

The clock generation unit 105 generates clock pulses for the pilot symbol arrangement unit 104 and the pilot symbol arrangement control unit in the time domain 106.

The nodes of the arrangement of pilot symbols 104 and the formation of clock pulses 105 can be performed similarly - according to the structural diagrams of the nodes of the arrangement of pilot symbols and the formation of clock pulses in the frequency domain, i.e. as shown in FIGS. 8 and 9.

The block diagram of the control unit placement of the pilot symbols in the time domain is shown in Fig.

The control unit of the placement of the pilot symbols in the time domain 106 operates as follows.

The duration of the control signals generated by the pilot symbol arrangement control unit in the time domain 106 and their time shifts relative to each other are determined by five counters. The first counter 113 determines the duration of the control signals of the placement of the data symbols (Sim Dan) and the installation of pilot signals (MS). The second counter 114 determines the number of modulated data symbols located between the pilot symbols in the time domain N _t . The third counter 115 determines the duration of the control signals — the first recording signal (Rec 1) and the second recording signal (Rec 2). The fourth counter 116 determines the period T ₁ with which, for a predetermined time T ₂ (fifth counter 117), the minimum set value N _t = N _{tmin is} assigned to the number of modulated data symbols located between the pilot symbols in the time domain _. .

The control signal of the initial installation (NU) sets the first trigger 118 in such a way that from its first output a control signal for the arrangement of data symbols (Sim Dan) is output to the control unit 106, and the second trigger 119 in such a way that a control signal for a first AND gate 107. in this case, the shift clock via a first AND gate 107 are input to the first counter 113, which upon receipt of N _f clock generates shift pulses at the first output control signal behaving minutes on the first trigger 118. In this control signal the first flip-flop 118 goes into a state in which its output enters the second control signal setting the pilot signal (PS). The control signal for setting the pilot signal is supplied to the output of node 106. After the next N _f +1 clock pulse is received at the first counter 113, a control signal is received from its second output, which sets the first trigger 118 to a state in which from its first output node receives a control signal arrangement of data symbols, and from the second output is removed the control signal installation of the pilot signal. Thus, the first trigger 118 is switched K times, where K is the number of pilot symbols in the group of modulated symbols.

The control signal of the initial installation through the second logical element OR 126 also sets the fourth trigger 121 so that from its output a control signal is supplied to the second logical element AND 108. Moreover, from the first ROM 122 through the second logical element And 108 and the first logical element OR 125 in the first register 128 is written the minimum specified value of the number of modulated data symbols located between the pilot symbols in the time domain, N _t = N _tmin , which is then overwritten in the second counter 114.

The signal from the output of the second trigger 119 also goes to the fourth logical element And 110 and through the logical element NOT 130 to the fifth logical element And 111. Moreover, from the second ROM 123 through the fifth logical element And 110 and the third logical element OR 127 the number of modulated data symbols in a group of the second type, Q2 is recorded in the third counter 115 and is output to the control unit for arranging the pilot symbols in the time domain 106. When the second trigger 119 transitions to the opposite state from the third ROM 124 through the fifth logical element And 111 and the third logical element OR 127 the number of modulated data symbols in the group of the first type Q1 is recorded in the third counter 115 and is output to the node 106. Thus, Q takes two values Q1 and Q2.

The input of the third counter 115 receives input clock pulses. After the input of the third counter 115 Q clock pulses (the counter operates in the subtraction mode), this counter generates a control signal supplied to the third trigger 120. By this control signal, the third trigger 120 switches to the opposite state, in which its output control signals are the first signal recording and the second recording signal change their values to the opposite. Control signals - the first recording signal and the second recording signal are supplied to the corresponding outputs of the node 106.

The output control signal of the third counter 115 is also fed to the input of the second counter 114 and to the corresponding output of the node 106 as a write synchronization control signal (Sync Zap). After N _{t the} output signals of the third counter 115, the output signal of the second counter 114 is supplied to the second trigger 119 and sets it in such a way that the control signal supplied to the first logical element And 107 is removed from its output. In this case, the clock pulses of the shift (TI Sdv) are not received at the input of the first counter 113. From the first output of the first flip-flop 118, a data character arrangement control signal is received.

The input clock pulses through the seventh logic element And 112 are also sent to the fifth counter 117. After a time interval T2, the fifth counter 117 generates a control signal that sets the fourth trigger 121 to the opposite state, and also resets the fourth counter 116. In this case, the fourth trigger 121 goes into the opposite state and the input clock pulses through the sixth logical element AND 112 do not arrive at the fifth counter 117. After zeroing, the fourth counter 116 after a time interval T1 generates a signal that after The OR gate 126 sets the fourth trigger 121 to the opposite state. At the same time, from the first ROM 122 through the second logical element AND 108 and the first logical element OR 125, the minimum set value of the number of modulated data symbols located between the pilot symbols in the time domain, N _t = N _tmin , is written to the first register 128, which is then overwritten into the second counter 114. Next, the process of generating the output control signals of the control unit arrangement of the pilot symbols in the time domain is repeated.

Thus, the pilot symbol alignment control unit in the time domain 106 generates data symbol alignment and pilot symbol control signals. The duration of the data symbol arrangement signal (Sim Dan) is equal to the duration N _{f of the} modulated data symbols. The duration of the pilot setting signal (PS) is equal to the duration of one modulated data symbol. A pair of control signals for the arrangement of data symbols and the installation of pilot signals follow continuously one after another K times, where K is the number of pilot symbols in the group. To pairs of control signals — the arrangement of data symbols and the installation of pilot signals are separated from each other by a duration of N _t groups of modulated symbols. Moreover, with a given period T ₁ during a given time T ₂ assign the number of modulated data symbols located between the pilot symbols in the time domain, the minimum specified value N _t = N _tmin. .

The control unit arrangement of the pilot symbols in the time domain 106 also generates the following continuously overlapping control signals - the first recording signal (Zap 1) and the second recording signal (Zap 2). The duration of these signals is equal to the duration of the modulated data symbols of one group.

The node 106 also generates the number of modulated data symbols in one group Q and a write synchronization control signal (Sync Zap), which determines the time when the number of modulated data symbols in the group arrives at the output of the control node.

Thus, increasing the data transfer rate in OFDM communication systems is achieved:

- a method of transmitting / receiving data in a radio communication system according to the first embodiment, due to the fact that the distance between the pilot symbols in the frequency domain changes, and the distance between the pilot symbols in the time domain remains fixed;

- a method of transmitting / receiving data in a radio communication system according to the second embodiment, due to the fact that the distance between the pilot symbols in the time domain changes, and the distance between the pilot symbols in the frequency domain remains fixed;

- a method for evaluating the correlation interval of the received orthogonal frequency-mutiplexed symbols (options), the implementation of which is a prerequisite for the implementation of the method of transmitting and receiving data in a radio communication system (respectively options);

- a device for transmitting and receiving data in a radio communication system according to the first embodiment, by introducing into the device at the transmitting station a pilot signal arrangement unit in the frequency domain and, accordingly, new communications ensuring the implementation of all the features of the invention, and also by introducing into the device at the receiving station a block for estimating the correlation interval in the frequency domain and a block for generating a signal of the return channel and, accordingly, new connections ensuring the implementation of all the features of the invention;

- a device for transmitting / receiving data in a radio communication system according to the second embodiment, by introducing into the device at the transmitting station a pilot signal arrangement unit in the time domain and, accordingly, new communications providing all the features of the method on the transmitting side, as well as by introducing into the device at the receiving station, a block for estimating the correlation interval in the time domain and a block for generating a signal of the return channel and, accordingly, new connections, ensuring the implementation of all the signs of person on the receiving side.

Claims (6)

1. The method of transmitting and receiving data in a radio communication system, namely, that a sequence of binary characters is received at the transmitting station, the sequence is divided into words consisting of d characters, where d = 1, 2, ... G, each word is assigned a modulated data symbol in the form of a complex number, transform a sequence of modulated data symbols into parallel groups of two types, the first of which consists of Q1 modulated data symbols, where Q1 is a given number, the second of Q2 modulated data symbols, where Q2 this number, complement the groups of the first type with sequences consisting of Z zero characters, placing them at the beginning and the end of the group, and Q1 + 2Z = N, complement the groups of the second type with sequences consisting of Z zero characters, placing them at the beginning and the end of the group, and through every N _f modulated data symbols have a pilot symbol, where N _f = Q2 / K, with Q2 being a multiple of K and Q2 + 2Z + K = N, and K is the number of pilot symbols in a group of the second kind, form a sequence of groups of the first and second species so that groups of the second kind follow without every N _t groups of the first type, where N _{t is a} given number, while in groups of the second type separated by a given number V of groups of this type, the minimum set value is assigned to the number of modulated data symbols N _f located between the pilot symbols N _f = N _{f min} , with each group of the generated sequence, the inverse fast Fourier transform is performed, forming parallel output groups of values of the inverse fast Fourier transform, the parallel output groups of values of the inverse fast pre Fourier formation in a sequential form, thus forming a sequence of transmitted symbols, each of which contains N received successive inverse fast Fourier transform values, complement each transmitted symbol with a guard interval, thereby forming a sequence of orthogonal frequency-multiplexed symbols, transmit a sequence of orthogonal frequency-multiplexed symbols to the receiving station; they are received at the receiving station and the guard interval is removed, thus forming a sequence of received symbols, converting the received symbols into parallel groups of input values, perform fast Fourier transform with each group of input values, thus forming N modulated symbols in each group, according to pilot symbols groups of the second type, in which the number of modulated data symbols located between the pilot symbols N _f is assigned the minimum value N _f = N _{f min} , the correlation interval is estimated received modulated symbols in the frequency domain N _fcor , normalized to the frequency shift between subcarriers of the orthogonal frequency multiplexed symbol, transmit the obtained estimate of the duration of the correlation interval in the frequency domain to the transmitting station, in each group of the second type, the communication channel is estimated using the pilot symbols using the obtained results communication channel estimates, evaluate Q1 modulated data symbols of groups of the first kind and Q2 modulated data symbols of groups of the second kind, convert grouping the estimates of the modulated data symbols in a serial form, thereby forming a sequence of estimates of the modulated data symbols, performing demodulation of the resulting estimates of the modulated data symbols, thereby forming a sequence of binary data; at the transmitting station, the value of N _{f is} adjusted so that the condition N _f ≤N _{f cor is} satisfied, where N _f is the number of modulated data symbols located between the pilot symbols, and N _fcor is an estimate of the duration of the correlation interval in the frequency domain. 2. A method of transmitting and receiving data in a radio communication system, namely, that a sequence of binary characters is received at the transmitting station, the sequence is divided into words consisting of d characters, d = 1, 2, ... G, each word is assigned a modulated character data in the form of a complex number, transform a sequence of modulated data symbols into parallel groups of two types, the first of which consists of Q1 modulated data symbols, where Q1 is a given number, the second is from Q2 modulated data symbols, where Q2 is given a number, complement the groups of the first type with sequences consisting of Z zero characters, positioning them at the beginning and end of the group, and Q1 + 2Z = N, complement the groups of the second type with sequences consisting of Z zero characters, placing them at the beginning and end of the group, and through every N _f modulated data symbols have a pilot symbol, where N _{f is a} given number, with Q2 being a multiple of K and Q2 + 2Z + K = N, and K is the number of pilot symbols in a group of the second kind, form a sequence of groups of the first and second kinds such so that the groups of the second kind are blow through every N _t groups of the first type, where N _{t is the} number of modulated data symbols located between the pilot symbols in the time domain, while with a given period T ₁ for a given time T _{2 is} assigned the number of modulated data symbols located between the pilot symbols in time domain, minimum setpoint, N _t = N _tmin. , the inverse fast Fourier transform is performed with each group of the generated sequence, forming parallel output groups of inverse fast Fourier transform values, the parallel output groups of inverse fast Fourier transform values are converted into a serial form, thereby forming a sequence of transmitted symbols, each of which contains N received sequential values inverse fast Fourier transform, complement each transmitted character with a guard interval scrap, thus forming a sequence of orthogonal frequency-multiplexed symbols, transmit a sequence of orthogonal frequency-multiplexed symbols to a receiving station, receive them at the receiving station and remove the guard interval, thereby forming a sequence of received symbols, convert the received symbols to parallel groups of input values, with each group of input values performs fast Fourier transform, thus forming N modulated symbols in each group, according to the pilot symbols of groups of the second type, which are transmitted with a predetermined period T ₁ during a predetermined time T ₂ , when the number of modulated data symbols located between the pilot symbols in the time domain takes a minimum predetermined value, N _t = N _{t min} , estimate the duration of the correlation interval in the time domain N _tcor normalized to the duration of the orthogonal frequency-multiplexed symbols received modulated symbols, transmit the resulting estimate of the duration of the correlation interval in the time domain On the transmitting station, in each block, the pilot symbols are used to evaluate the communication channel using the obtained communication channel estimation results, Q1 modulated data symbols of the first kind and Q2 modulated data symbols of the second kind are evaluated, groups of modulated data symbol estimates are converted to serial form, thus forming a sequence of estimates of modulated data symbols, perform demodulation of the obtained estimates of modulated data symbols, thereby forming a sequence atelnost binary data at the transmitting station size N _t is adjusted so as to satisfy the condition N _t ≤N _tcor, where N _t - the number of modulated data symbols located between the pilot symbols in the time domain, N _tcor - correlation interval duration in the time domain . 3. A method for estimating the correlation interval of received orthogonal frequency-multiplexed symbols, which consists in the fact that in the groups of modulated data symbols of the second type obtained after the FFT, in which the number of modulated data symbols located between the pilot symbols N _f is assigned the minimum value N _f = N _{f min} , at the beginning and the end, sequences consisting of Z zero symbols are deleted, interpolation of the pilot symbols at the points of modulated data symbols is performed, thus forming a sequence of pilot oxen, consisting of the received and interpolated pilot symbols, calculate the cyclic correlation function of the generated pilot symbol sequence, calculate the module of the obtained cyclic correlation function of the pilot symbol sequence, determine the extrema of the module of the obtained correlation function of the pilot symbol sequence and compare them with the threshold, select the extrema exceeding a predetermined threshold and determine the distance between them, and then average these distances, thus obtaining the value of The correlation interval in the frequency domain of the received orthogonal frequency-multiplexed symbols. 4. A method for estimating the magnitude of the correlation interval of the received orthogonal frequency-multiplexed symbols, which consists in storing W groups of modulated symbols received after the FFT, which contain pilot symbols and which are transmitted with a given period T ₁ for a given time T ₂ when number of modulation data symbols located between the pilot symbols in the time domain, assumes a minimum given value, N _t = N _{t min,} stored in groups of modulated symbols at the beginning and end of SEQ removed The functions consisting of Z null symbols form K sequences of pilot symbols, allocating for each of K sequences one pilot symbol with the same number from each of W groups of modulated symbols, interpolate from each of K sequences of pilot symbols at points of modulated data symbols located between them, thus forming K sequences of pilot symbols consisting of received and interpolated pilot symbols, K cyclic correlation functions of of the pilot symbol sequences calculated, K modules of the obtained cyclic correlation functions of the pilot symbol sequences are calculated, the extrema of each of the K modules of the obtained correlation functions of the pilot symbol sequences are determined and compared with a threshold, extrema exceeding the threshold are extracted for each of the K modules of correlation functions, and average the distances between them, average the obtained average distances between the extrema, thus obtaining the average value of the average distances between to extrema, which is used as an estimate of the value of the correlation interval of the received orthogonal frequency-multiplexed symbols in the time domain. 5. A device for transmitting and receiving data in a radio communication system containing a transmitting and receiving station, wherein the transmitting station comprises a modulator, an inverse fast Fourier transform unit, a parallel-serial conversion unit, a guard interval attachment unit, a transmitter, a receiver, a splitter and an antenna, this input of the modulator is the first input of the transmitting station, is the input of a sequence of binary characters, the output of the transmitter is connected to the first input of the splitter, the first output of which one with a first input of the antenna, a first output and a second input of which are respectively inlet and outlet of the second transmitting station outputs a frequency-multiplexed symbols, the second output of the antenna connected to the second input coupler, the second output of which is connected to the receiver input; the receiving station contains an antenna, a splitter, a receiver, a transmitter, a block-parallel-parallel conversion and removal of the guard interval, a fast Fourier transform block, a channel estimator, a parallel-serial conversion block and a demodulator, wherein the first input of the antenna is the first input of the receiving station, the input frequency-multiplexed symbols, the first output of the antenna is connected to the first input of the splitter, the first output of which is connected to the input of the receiver, the output of which is connected to the first input of the serial-parallel conversion unit and removing the guard interval, the outputs of which are connected respectively to the inputs of the fast Fourier transform unit, the outputs of which are connected to the inputs of the channel estimator, the outputs of which are connected to the inputs of the parallel-serial conversion unit, the output of which is connected to the input of the demodulator, the output of which is the first output of the receiving station, forming a sequence of binary data on this output, the output of the transmitter is connected to the second input of the splitter, the second output of which is connected to the second input of the antenna, the second output of which is the second output of the receiving station, characterized in that the pilot station in the frequency domain is introduced at the transmitting station, the first input of which is connected to the output of the modulator, the second input of the block the arrangement of pilot signals in the frequency domain is combined with the first input of the attachment unit of the guard interval, forming the third input of the transmitting station, which is the input of the initial setup signal, the third the stroke of the pilot signal arrangement block in the frequency domain is connected to the receiver output, the outputs of the pilot signal alignment block in the frequency domain are connected to the inputs of the inverse Fourier transform block, the outputs of which are connected to the inputs of the parallel-serial conversion block, the output of which is connected to the second input of the connection block protective interval, the output of which is connected to the input of the transmitter; at the receiving station, a correlation interval estimation block in the frequency domain and a reverse channel signal generating block are introduced, while the inputs of the correlation interval estimation block in the frequency domain are connected to the outputs of the fast Fourier transform unit, the output of the correlation interval estimation block in the frequency domain is connected to the input of the signal conditioning block the return channel, the output of which is connected to the input of the transmitter, the second input of the serial-parallel conversion and removal of the guard interval is the second th input receiving station, the input signal the initial installation. 6. A device for transmitting / receiving data in a radio communication system containing a transmitting and receiving station, wherein the transmitting station comprises a modulator 4, an inverse fast Fourier transform unit, a parallel-serial conversion unit, a guard interval attachment unit, a transmitter, a receiver, a splitter and an antenna, wherein the input of the modulator is the first input of the transmitting station, is the input of a sequence of binary characters, the output of the transmitter is connected to the first input of the splitter, the first output of which oedinen antenna to the first input, a first output and a second input of which are respectively inlet and outlet of the second transmitting station outputs a frequency-multiplexed symbols, the second output of the antenna connected to the second input coupler, the second output of which is connected to the receiver input; the receiving station contains an antenna, a splitter, a receiver, a transmitter, a block-parallel-parallel conversion and removal of the guard interval, a fast Fourier transform block, a channel estimator, a parallel-serial conversion block and a demodulator, wherein the first input of the antenna is the first input of the receiving station, the input frequency-multiplexed symbols, the first output of the antenna is connected to the first input of the splitter, the first output of which is connected to the input of the receiver, the output of which is connected to the first input of the serial-parallel conversion unit and removing the guard interval, the outputs of which are connected respectively to the inputs of the fast Fourier transform unit, the outputs of which are connected to the inputs of the channel estimator, the outputs of which are connected to the inputs of the parallel-serial conversion unit, the output of which is connected to the input of the demodulator, the output of which is the first output of the receiving station, forming a sequence of binary data on this output, the output of the transmitter is connected to the second input of the splitter, the second output of which is connected to the second input of the antenna, the second output of which is the second output of the receiving station, characterized in that the pilot station in the time domain is introduced at the transmitting station, the first input of which is connected to the output of the modulator, the second input of the block the arrangement of pilot signals in the time domain is combined with the first input of the attachment block of the guard interval, forming the third input of the transmitting station, which is the input of the initial setting signal, the input of the pilot signal alignment block in the time domain is connected to the receiver output, the outputs of the pilot signal alignment block in the time domain are connected to the inputs of the inverse Fourier transform block, the outputs of which are connected to the inputs of the parallel-serial conversion block, the output of which is connected to the second input of the block attaching a guard interval whose output is connected to the input of the transmitter; at the receiving station, a time domain correlation interval estimator and a reverse channel signal generating unit are introduced, while the inputs of the time domain correlation interval estimator are connected to the outputs of the fast Fourier transform unit, the output of the time domain correlation interval estimator is connected to the input of the signal conditioning unit the return channel, the output of which is connected to the input of the transmitter, the second input of the block of serial-parallel conversion and removal of the protective interval is orym input of the receiving station, the input signal the initial installation.

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