CN200987177Y - Equipment for evaluating channel to incoming signal - Google Patents

Abstract

The utility model discloses a device for estimating the channel of an input signal, wherein different parts of the input signal are modulated with different modulation types, and the device comprises: a buffer for storing the input signal; a first derotator for The training sequence in the signal is derotated; the synchronizer processes the signal obtained after derotation; the channel estimator performs synchronization on the synchronization position information obtained after correlation processing by the synchronizer, the signal obtained after derotation and the known training sequence Channel estimation; the channel estimation converter transforms the channel estimation corresponding to the first modulation type obtained after channel estimation into the channel estimation corresponding to the second modulation type; the second derotator performs the information sequence in the input signal derotation; an equalizer that uses the transformed channel estimate to demodulate the derotated information sequence to obtain definite symbols. Applying the device described in the utility model realizes providing correct channel estimation for the input signal.

Description

A device for estimating the channel of an input signal

technical field

The utility model relates to a general device, in particular to a device for estimating a channel of an input signal.

Background technique

In a communication system comprising a transmitter and a receiver, the information exchanged between the transmitter and receiver, comprising data bits and synchronization bits, is modulated for transmission. In some cellular communication systems, it is advantageous to use one modulation type for the first part of the transmitted signal (for example, the part used for synchronization and channel estimation) and to use one modulation type for the second part of the transmitted signal (for example, the part containing ) using another modulation type, which allows selection of the modulation type for efficient transmitter implementation. For an efficient transmitter structure, an offset is usually introduced in the modulation format. Here, offset means that the symbol constellation is rotated by π/8 radians between adjacent symbols. This rotation produces a transmitted signal with a low peak-to-average ratio and no zero crossings, allowing for an efficient transmitter architecture.

On the receiver side, the received signal must be derotated in order to correctly detect the received symbols. However, due to multipath fading of radio waves, the rotation of the received signal results in a radio channel estimate as a function of the offset rotation.

Information in cellular radio communication systems is typically transmitted in bursts containing a synchronization signal, such as a training sequence, and an information sequence. If the entire burst is sent with the same modulation format, there will be a negative impact caused by the channel estimate as a function of the offset rotation. However, if one modulation type with a certain offset is used for the training sequence and another modulation type with another offset is used for the information sequence, the channel estimate obtained for the first modulation type must be transforms into a correct channel estimate corresponding to the second modulation type. Therefore, there is a need for an apparatus for converting a channel estimate obtained for one modulation type into a corresponding channel estimate obtained for another modulation type.

Utility model content

The technical problem to be solved by the utility model is to provide a device for estimating the channel of an input signal, so as to transform the channel estimation corresponding to one modulation type into the corresponding channel estimation corresponding to another modulation type.

In order to solve the above technical problems, the utility model provides a device for estimating the channel of the input signal, wherein different parts of the input signal are modulated using different modulation types, the device includes: a buffer, a first derotator, a synchronizer, A channel estimator, a channel estimation converter, a second derotator, and an equalizer, wherein the first derotator is cascaded after the buffer, and performs derotation on the first part of the input signal in the buffer to obtain a signal suitable for the second A signal of a modulation type, the synchronizer is connected to the first derotator, and the derotated signal is processed to determine the synchronization position information of the first part of the signal in the received burst, and the synchronizer is connected to the The channel estimator performs channel estimation on the synchronization position information, the signal obtained after derotation and the known training sequence, and the channel estimation converter connected to the channel estimator performs channel estimation corresponding to the first modulation type obtained after channel estimation Transforming the channel estimate to obtain a channel estimate corresponding to the second modulation type; the second derotator is cascaded after the buffer to derotate the second part of the input signal to obtain a channel estimate suitable for the second modulation type. For signals of the modulation type, the equalizer connected to the second derotator performs equalization processing on the signal suitable for the second modulation type and the channel estimate corresponding to the second modulation type, to obtain a signal representing the second modulation type confirmation symbol.

Wherein, the buffer stores the input signal.

Wherein, the first part of the input signal is a training sequence. The training sequence is the input signal modulated using the first modulation type.

Wherein, the synchronizer performs synchronization processing on a signal suitable for the first modulation type and a known training sequence.

Wherein, the channel estimation converter processes the channel estimation of the first modulation type and the known training sequence.

Wherein, the second part of the input signal is an information sequence. The information sequence is an input signal modulated using a second modulation type.

Wherein, the channel estimate corresponding to the second modulation type is used in the equalizer to demodulate a signal suitable for the second modulation type.

The device described in the utility model transforms the channel estimate obtained corresponding to one modulation type into the corresponding channel estimate obtained corresponding to another modulation type, so that when different parts of the input signal are used by more than one Provides a correct channel estimate for the input signal when modulated by the modulation type.

Description of drawings

Fig. 1 is a schematic structural diagram of a device for estimating a channel of an input signal according to an embodiment of the present invention.

Detailed ways

The following description is directed to a cellular wireless communication system, but the present invention is not limited thereto, and can also be applied to other types of communication systems.

Referring to FIG. 1 , it is a schematic structural diagram of a device for estimating the channel of an input signal according to an embodiment of the present invention, which specifically includes: a buffer, a first derotator, a synchronizer, a channel estimator, a channel estimation converter, a second Two solution rotator, equalizer.

a buffer for storing the input signal;

The first derotator is used to derotate the training sequence in the input signal to obtain a signal suitable for the first modulation type;

The synchronizer is used to correlate the signal obtained after derotation with the known training sequence, and obtain the synchronous position information of the training sequence in the input signal appearing in the receiving burst;

A channel estimator, configured to perform channel estimation on the synchronization position information, the signal obtained after derotation, and the known training sequence, to obtain channel estimation corresponding to the first modulation type;

A channel estimation converter, configured to process the channel estimation of the first modulation type and the known training sequence, and transform the channel estimation corresponding to the first modulation type into the channel estimation corresponding to the second modulation type;

The second derotator is used to derotate the information sequence in the input signal to obtain a signal suitable for the second modulation type;

The equalizer is used to equalize the signal suitable for the second modulation type and the channel estimation corresponding to the second modulation type, so as to obtain definite symbols representing the second modulation type.

An input signal from a transmitter of a base station is converted into a baseband signal, sampled with a predetermined burst length and stored in a buffer.

The information sequence in the input signal stored in the buffer passes through the first derotator, and is derotated by the derotator to obtain a signal suitable for the first modulation type, which is then fed into the synchronous In the synchronizer, the synchronizer correlates the signal with the known training sequence of the communication system in order to determine where the training sequence in the input signal occurs in the received burst and determine the synchronization, that is, to obtain the frequency of the training sequence occurring in the received burst Synchronize location information. A synchronizer can be implemented with any type of conventional synchronization device.

Then, the information representing the start or synchronization position of the training sequence, the derotated signal and the known training sequence are input to the channel estimator, which estimates that with respect to the input signal modulated with the first modulation type, the estimator can use any Types of traditional channel estimators implemented, such as the least squares estimator. The output from the channel estimator, that is, the channel estimate corresponding to the first modulation type and the known training sequence is fed into a channel estimate converter, which transforms the channel estimate corresponding to the first modulation type into a channel estimate corresponding to Channel estimation for the second modulation type.

The information sequence in the input signal stored in the buffer is passed through the second derotator, and derotated by the derotator to obtain a signal suitable for the second modulation type, and then suitable for the second modulation A signal of type λ is input to an equalizer, which may be of any type, such as a maximum likelihood sequence estimator equalizer described in Digital Communications, together with a channel estimate corresponding to a second modulation type. The transformed channel estimate is used to demodulate the derotated information sequence in an equalizer whose output is the determined symbol.

The utility model provides an effective device for transforming a channel estimate obtained for one modulation type into a corresponding channel estimate for another modulation type. The transformation is a function for different modulation types and known training sequences, and thus can be precomputed and stored in a buffer, allowing for an efficient implementation. The transformed channel estimate is then used in an equalizer to decode the received data.

Those skilled in the art should understand that the utility model can be implemented in other definite forms without departing from the essential features of the utility model. Therefore, the description of the above embodiments should be considered as illustrative and not restrictive in any respect. Although the above has been described with reference to mobile stations and base stations in a cellular communication system, the invention is also applicable to other types of communication systems.

Claims (1)

1. equipment of input signal being estimated channel, wherein the different piece of input signal uses different modulation types to modulate, it is characterized in that, comprise: buffer, first derotator, synchronizer, channel estimator, the channel estimating converter, second derotator, equalizer, wherein, the first derotator level is coupled to after the buffer, first's signal to input signal in the buffer carries out derotation, obtain being suitable for the signal of first kind of modulation type, described synchronizer is connected with first derotator, signal after the derotation is handled to determine the sync bit information of first's signal appearance in receiving burst, the channel estimator that is connected with synchronizer is to described sync bit information, signal that obtains after the derotation and known training sequence are carried out channel estimating, the channel estimating corresponding to first kind of modulation type that the channel estimating converter that is connected with channel estimator obtains after to channel estimating is carried out conversion process, obtains the channel estimating corresponding to second kind of modulation type; The described second derotator level is coupled to after the buffer, second portion signal to input signal carries out derotation, obtain being suitable for the signal of second kind of modulation type, the equalizer that is connected with second derotator carries out equilibrium treatment to the signal that is suitable for second kind of modulation type and described channel estimating corresponding to second kind of modulation type, obtains representing definite symbol of second kind of modulation type.

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