CN107819558B - A kind of multiple access data packet transmission method - Google Patents
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Abstract
一种多址接入数据包传输方法，将前导序列和数据同时发送，并将用于用户检测的导频集中分配在一个相干时频资源块内，将用于用户信道估计的导频分散在不同相干时频资源块内，实现了基于合并连续发送前导序列与数据、分离用户检测与信道估计的优化方法。该方法减少了随机接入过程中用户和基站之间的信令交互，从而降低了数据传输延时，基于分离活跃用户检测与信道估计方法不仅可以得到高精度的信道响应值，而且具有较低的导频开销。因此本发明提供的方法可以降低数据传输延时，并在较低导频开销的情况下获得高精度的信道响应值，进而为数据解调提供良好的基础。
A multiple access data packet transmission method, the preamble sequence and data are sent at the same time, the pilot frequency used for user detection is centrally allocated in a coherent time-frequency resource block, and the pilot frequency used for user channel estimation is scattered in the In different coherent time-frequency resource blocks, an optimization method based on combining consecutively transmitted preamble sequences and data and separating user detection and channel estimation is implemented. The method reduces the signaling interaction between the user and the base station in the random access process, thereby reducing the data transmission delay. Based on the method of separating active user detection and channel estimation, not only high-precision channel response values can be obtained, but also low pilot overhead. Therefore, the method provided by the present invention can reduce the data transmission delay, and obtain a high-precision channel response value under the condition of lower pilot frequency, thereby providing a good foundation for data demodulation.
Description
Technical Field
The invention belongs to the technical field of multiple access mobile communication, and particularly relates to a multiple access data packet transmission method.
Background
A Multiple Access (MA) scheme may enable Multiple users to simultaneously use a shared communication channel. In the field of mobile communication, before a user sends useful data, a Preamble sequence (Preamble) is sent for uplink synchronization and uplink resource application, and then a random access response signaling sent by a base station is received. In the current LTE network, signaling interaction is required to be performed 4 times between a user and a base station in a random access process to establish a connection, and after the random access process, data transmission is performed normally between the user and the base station. If the data volume of single communication of the user is small, the signaling interaction of the existing multiple access process is long.
Disclosure of Invention
In order to overcome the drawbacks of the prior art, an object of the present invention is to provide a multiple access data packet transmission method, in which a preamble sequence and data are simultaneously transmitted, the preamble sequence uses a non-orthogonal pilot sequence to generate more sequences to support more users, and pilot frequencies for user detection are centrally allocated in one coherent time-frequency resource block, and pilot frequencies for user channel estimation are dispersed in different coherent time-frequency resource blocks, thereby realizing direct data transmission without signaling interaction, reducing signaling overhead, reducing delay, and reducing pilot frequency overhead for multiple users.
In order to achieve the purpose, the invention adopts the technical scheme that:
a transmission method of multiple access data packet is characterized in that preamble sequence and data are transmitted simultaneously, pilot frequency for user detection is distributed in a coherent time frequency resource block in a centralized way, and pilot frequency for user channel estimation is dispersed in different coherent time frequency resource blocks, the steps are as follows:
1) the base station distributes a pilot frequency sequence different from other users to new users entering the coverage area of the base station, but the resources occupied by each user are completely synchronous in advance, the time frequency resources for inserting the pilot frequency and the data are common, the pilot frequency sequences between different users are non-orthogonal, the time frequency resources for inserting the pilot frequency sequences are divided into two types, one type is a user detection unit, namely more pilot frequencies are inserted into a coherent time frequency resource block for user detection, and the other type is a channel estimation unit, namely less pilot frequencies are uniformly and dispersedly inserted into a plurality of coherent time frequency resource blocks for channel estimation;
2) when any user has data service transmission requirement, the user sends pre-distributed pilot frequency sequence in the pre-defined wireless communication time frequency resource, the pilot frequency sequence and data are transmitted together, the data symbol coding modulation adopts a distinguishable multiple access mode, and multiple access coding or interweaving patterns used by the user are bound with the user pilot frequency sequence one by one;
3) the base station utilizes compressed sensing to carry out user detection and channel estimation according to the pilot frequency inserted by the user detection unit to obtain an active user set and channel response of the active user in the user detection unit;
4) the base station carries out channel estimation according to the active user set obtained in the step 3) and the pilot frequency inserted by the channel estimation unit to obtain the channel response of the active user in the rest time-frequency resources;
5) the base station completes multi-user data demodulation, completes one-time data packet transmission if the data demodulation of a certain user is correct, and starts an error processing mechanism if the data demodulation of the certain user is incorrect.
In the user detection unit, the number of the pilot frequencies inserted in a coherent time frequency resource block is more than 4 times of the maximum number of active users; in the channel estimation unit, the number of the pilot frequencies inserted in each coherent time-frequency resource block is more than or equal to the maximum number of active users and is less than 4 times of the maximum number of the active users.
In the step 2), the pilot symbols adopt amplitude modulation or phase modulation; the data symbols are coded and modulated by adopting sparse code multiple access, non-orthogonal multiple access, interleaving multiple access or code division multiple access.
Compared with the prior art, the invention has the beneficial effects that:
by combining the continuous sending leader sequence and data, the signaling interaction between the user and the base station in the random access process is reduced, the transmission delay is reduced, the detection capability of user conflict is improved by introducing a distinguishable multiple access mode, and by adopting a non-orthogonal pilot frequency sequence and a pilot frequency structure for separating active user detection and channel estimation, a high-precision channel response value can be obtained, and the pilot frequency overhead is lower. Therefore, the method provided by the invention can obtain a high-precision channel response value under the condition of low pilot frequency overhead, thereby providing a good basis for data demodulation.
Drawings
Fig. 1 is a flow chart of a packet transmission scheme.
Fig. 2 is a pilot design.
Fig. 3 is a flow chart of an implementation of the present invention.
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the drawings and examples.
Referring to fig. 1, a user sends a preamble and data in a contention mode on pre-allocated time-frequency resources, and one-time data packet transmission can be completed without signaling interaction between the user and a base station.
The invention transmits the leader sequence and data at the same time, the leader sequence adopts Non-Orthogonal pilot frequency sequence to generate more sequences to support more users, the pilot frequency symbol adopts traditional amplitude modulation or phase modulation, the data symbol coding modulation adopts any distinguishable Multiple Access mode, including but not limited to Sparse Code Multiple Access (SCMA), Non-Orthogonal Multiple Access (NOMA), interleaved Multiple Access (IDMA), Code Division Multiple Access (CDMA), and the pilot frequency for user detection is distributed in a coherent time frequency resource block in a centralized way, and the pilot frequency for user channel estimation is dispersed in different coherent time frequency resource blocks.
In the uplink system adopting the transmission method, the user can transmit data in a competitive mode on the preset resource block without a request/permission process. This requires the receiving end to detect active users, perform multi-user channel estimation and data demodulation without knowing which user codebook and pilot are included in the received signal.
In order to deal with the scenario of accessing massive users, if the users are all allocated with orthogonal pilot sequences, the pilot overhead is too large, so that the users are allocated with non-orthogonal pilot sequences. In large-scale user multiple access, only a small part of active users are accessed at the same time, and the active users can be considered to be sparse compared with all the users of the system, so that user detection can be converted into a compressed sensing problem. The pilot sequence supports two functions of user detection and channel estimation. From the user quantity perspective, user detection needs to identify a small part of active users from a large number of potential users, and channel estimation only estimates channels of the active users, and the user detection faces more users.
From the time-frequency perspective, in dispersive channels, time/frequency selective fading can bring greater challenges to user detection and channel estimation. In a dispersive channel, the channel response of each user can be considered to be almost unchanged within the coherence time and the coherence bandwidth, the whole resource can be divided into a plurality of coherent time-frequency resource blocks according to the coherence time and the coherence bandwidth, and the channel response of each user can be considered to be unchanged within the coherent time-frequency resource blocks, so that uniform signal processing can be performed in the blocks. Assuming that the time-frequency resources occupied by each user in the multiple access are completely synchronous, only one time of user detection needs to be performed in the time-frequency resources uniformly, and in a dispersive channel, each coherent time-frequency resource block needs to be subjected to channel estimation respectively. The distribution pattern of the pilot frequency is optimally designed by utilizing the characteristic, the pilot frequency used for user detection is intensively distributed in one coherent time frequency resource block, and the pilot frequency used for user channel estimation is dispersed in different coherent time frequency resource blocks. The pilot frequency resources of the user detection part are more because too many potential users need to be identified, and the number of the pilot frequency resources is more than 4 times of the number of the identifiable simultaneous users according to the compressed sensing theory, so the pilot frequency used for user detection is intensively distributed in a coherent time frequency resource block, and the number of the pilot frequency resources is more than 4 times of the number of the identifiable simultaneous users, namely the maximum number of active users. When the active user set is known, even if the number of the pilots is equal to the number of the active users, the probability of the lack of rank of the formed pilot matrix is very low due to the difference of the pilots, and the channel response can be estimated as long as the number of the pilots is slightly larger than the number of the users, so that the pilots for user channel estimation are dispersed in different coherent time-frequency resource blocks, and the number of the channel estimation pilots in one coherent time-frequency resource block is less than 4 times of the number of the active users. The pilot distribution pattern thus designed reduces pilot overhead and ensures simultaneous access by a large number of users.
Fig. 2 shows a time-frequency resource mapping method of pilot frequency and data, where the abscissa shows time, the ordinate shows frequency, a grid represents time-frequency resources occupied by data packets sent by users, time-frequency resource blocks are divided according to channel coherence time and coherence bandwidth in a typical transmission environment, the span of each coherent time-frequency resource block is less than or equal to the minimum coherence time delay/bandwidth, and thus, in each time-frequency resource block, the channel response of a user can be considered as a fixed value. Selecting a coherent time-frequency resource block set with more pilot frequencies inserted for user detection as a user detection unit; and other coherent time-frequency resource blocks are uniformly dispersed, less pilot frequency is inserted for channel estimation and used as a channel estimation unit, and time-frequency resources except the pilot frequency are used for transmitting data.
The data symbol code modulation supports any distinguishable multiple access mode, but multiple access codes or interleaving patterns used by users must be bound with user pilot sequences one by one, so that user detection is carried out according to the user detection pilot sequences, not only an active user set can be determined, but also the multiple access codes or interleaving patterns adopted by the users can be determined. In the distinguishable multiple access mode, the data of different users can be distinguished by utilizing the respective coding or interleaving pattern information of the users, so that the user data can be demodulated.
FIG. 3 is a flow chart of an implementation corresponding to various steps of the present invention, as follows:
1) the base station allocates a pilot frequency sequence different from other users to a new user entering the coverage area of the base station, but the resources occupied by each user are specified to be completely synchronous in advance, and the pilot frequency sequence consists of a Zadoff-Chu sequence and a shift sequence thereof. The time frequency resources for inserting the pilot frequency and the data are common, the pilot frequency sequences between different users are non-orthogonal, the time frequency resources for inserting the pilot frequency sequences are divided into two types, one type is a user detection unit, namely more pilot frequencies are inserted into one coherent time frequency resource block, the number of the pilot frequencies is more than 4 times of the maximum active user number and is used for user detection, the other type is a channel estimation unit, namely less pilot frequencies are uniformly and dispersedly inserted into a plurality of coherent time frequency resource blocks, the number of the pilot frequencies is more than or equal to the maximum active user number and is less than 4 times of the maximum active user number and is used for channel estimation;
2) when any user has data service transmission requirement, the user sends pre-distributed pilot frequency sequence in the pre-defined wireless communication time-frequency resource, the effect of the method on user access is equivalent to that of a leader sequence in the existing communication system, the pilot sequence and data are transmitted together, the pilot symbols adopt the traditional amplitude modulation or phase modulation, the data symbol coding modulation adopts any distinguishable multiple access mode including but not limited to sparse code multiple access, non-orthogonal multiple access, interleaving multiple access and code division multiple access, multiple access coding or interleaving patterns used by users are bound with the user pilot sequences one by one, taking the interleaving multiple access as an example, each pilot sequence corresponds to an interleaving pattern, once it is determined that a pilot sequence is transmitted by an active user during user detection, the interleaving pattern used by the user can be determined, and the data of the user can be demodulated by using the interleaving pattern.
3) And the base station performs user detection and channel estimation by adopting a Sparse Bayesian Learning-based method (Sparse Bayesian Learning) according to the pilot frequency inserted by the user detection unit to obtain an active user set and a channel response of the active user in the user detection unit. Firstly, a pilot frequency relational expression received by a user detection unit is real: it is not to be noted that the user detection unit is data block 1, in which the received pilot resource vector is used
Denotes, digitizes it, here
The channel value and the active flag (the value of the inactive user is 0, and the value of the active user is the channel response value) of the total potential active users in the data block 1 are shown, phi1A pilot code matrix in data block 1 is represented,
wherein
And
representing the real and imaginary parts, respectively.
Assuming that the channel responses of all potential active users to be recovered satisfy a gaussian distribution with a mean value of 0 and a variance of γ (the finally obtained γ is 0 corresponding to user inactivity and γ is non-zero corresponding to user activity), the initial value γ of the variance is(0)All 0 s can be set.
Gamma from the k-th iteration according to the following formula(k)Gamma of the k +1 th time is obtained by calculation(k+1)：
Γ(k)＝diag(γ(k))
Until a maximum number of iterations is reached or satisfied
(. e represents the channel estimation accuracy), the iteration ends.
Vector the mean value in the iterative process
As a return value, obtain
By performing a complex:
and obtaining a vector to be solved, and further obtaining the position of the pilot frequency code selected by the active user and the channel response of the pilot frequency code in the user detection unit.
4) The base station carries out channel estimation according to the active user set obtained in the step 3) and the pilot frequency inserted by the channel estimation unit, and extracts the pilot frequency codes at the corresponding positions of the active users from the channel estimation unit to form a new pilot frequency code matrix; numbering the channel estimation unit as data block j, and detecting result psi according to active user in j-th data blockj＝Φj(active)(i.e. extracting a new matrix formed by pilot sequences at the positions of active users in the original pilot code matrix), obtaining the channel response values of the active users by utilizing a zero-forcing algorithm or a minimum mean square error method,wherein the Zero Forcing (ZF) algorithm:
minimum mean square error algorithm (MMSE):
(Here, the
Channel estimation vector, Ψ, representing the inclusion of only active users in the jth data blockjIndicating a pilot code matrix containing only active users,
still represents the pilot resource vector received by the jth data block, but because the received pilot resource vector can be considered to be influenced only by the active user on the basis of detecting the active user, the received pilot resource vector can be used
Is shown)
5) The base station completes multi-user data demodulation, if the data demodulation of a user is correct, one-time data packet transmission is completed, if the data demodulation of the user is incorrect, an error processing mechanism is started.
In summary, the present invention realizes an optimization method based on merging of continuous transmission preamble sequences and data and separation of user detection and channel estimation by simultaneously transmitting preamble sequences and data, intensively allocating pilot frequencies for user detection in one coherent time-frequency resource block, and dispersing pilot frequencies for user channel estimation in different coherent time-frequency resource blocks. The method reduces the signaling interaction between the user and the base station in the random access process, thereby reducing the data transmission delay, and not only can obtain a high-precision channel response value but also has lower pilot frequency overhead based on the separation active user detection and channel estimation method. Therefore, the method provided by the invention can reduce the data transmission delay, and obtain the high-precision channel response value under the condition of lower pilot frequency overhead, thereby providing a good basis for data demodulation.
Claims (2)
1. A transmission method of multiple access data packet is characterized in that preamble sequence and data are transmitted simultaneously, pilot frequency for user detection is distributed in a coherent time frequency resource block in a centralized way, and pilot frequency for user channel estimation is dispersed in different coherent time frequency resource blocks, the steps are as follows:
1) the base station distributes a pilot frequency sequence different from other users to new users entering the coverage area of the base station, but the resources occupied by each user are completely synchronous according to the presetting, the time frequency resources for inserting the pilot frequency and the data are common, the pilot frequency sequences among different users are non-orthogonal, the time frequency resources for inserting the pilot frequency sequences are divided into two types, one type is a user detection unit, namely, the pilot frequency is inserted into a coherent time frequency resource block for user detection, wherein the number of the pilot frequency inserted into one coherent time frequency resource block is more than 4 times of the maximum number of active users; the other type is a channel estimation unit, namely pilot frequencies are uniformly and dispersedly inserted into a plurality of coherent time-frequency resource blocks for channel estimation, wherein the number of the pilot frequencies inserted into each coherent time-frequency resource block is more than or equal to the number of the maximum active users and is less than 4 times of the number of the maximum active users;
2) when any user has data service transmission requirement, the user sends pre-distributed pilot frequency sequence in the pre-defined wireless communication time frequency resource, the pilot frequency sequence and data are transmitted together, the data symbol coding modulation adopts a distinguishable multiple access mode, and multiple access coding or interweaving patterns used by the user are bound with the user pilot frequency sequence one by one;
3) the base station performs user detection and channel estimation by adopting a sparse Bayesian learning-based method according to the pilot frequency inserted by the user detection unit to obtain an active user set and channel response of the active user in the user detection unit;
firstly, a pilot frequency relational expression received by a user detection unit is real: let the user detection unit be data block 1, in which the received pilot resource vector is used
It is shown, converted into a number,
representing the channel value and the active flag of the total potential active users in the data block 1, the value of the inactive user is 0, the value of the active user is the channel response value, phi1A pilot code matrix represented in data block 1;
wherein
And
respectively representing a real part and an imaginary part;
assuming that the channel responses of all potential active users to be recovered satisfy the Gaussian distribution with the mean value of 0 and the variance of gamma, the finally obtained gamma is 0 corresponding to user inactivity, gamma is nonzero corresponding to user activity, and the initial value gamma of the variance is(0)Set to all 0 s;
gamma from the k-th iteration according to the following formula(k)Gamma of the k +1 th time is obtained by calculation(k+1)：
Γ(k)＝diag(γ(k))
Until a maximum number of iterations is reached or satisfied
Ending iteration, and representing the channel estimation precision by epsilon;
vector the mean value in the iterative process
As a return value, obtain
By performing a complex:
obtaining a vector to be solved, and further obtaining the position of the pilot frequency code selected by the active user and the channel response of the pilot frequency code in the user detection unit;
4) the base station carries out channel estimation according to the active user set obtained in the step 3) and the pilot frequency inserted by the channel estimation unit, and extracts the pilot frequency codes at the corresponding positions of the active users from the channel estimation unit to form a new pilot frequency code matrix; numbering the channel estimation unit as a data block j, and detecting a result psi according to an active user in the jth data blockj＝Φj(active)Extracting a new matrix formed by pilot sequences at the positions of active users in an original pilot code matrix, and obtaining the channel response values of the active users by utilizing a zero-forcing algorithm or a minimum mean square error method, wherein the zero-forcing algorithm comprises the following steps:
minimum mean square error algorithm:
channel estimation vector, Ψ, representing the inclusion of only active users in the jth data blockjIndicating a pilot code matrix containing only active users,
still indicates the pilot resource vector received by the jth data block, because the received pilot resource vector is considered to be influenced only by the active user on the basis of detecting the active user, the j data block is used
Represents;
5) the base station completes multi-user data demodulation, completes one-time data packet transmission if the data demodulation of a certain user is correct, and starts an error processing mechanism if the data demodulation of the certain user is incorrect.
2. The multiple access data packet transmission method according to claim 1, wherein in step 2), the pilot symbols are modulated by amplitude or phase; the data symbols are coded and modulated by adopting sparse code multiple access, non-orthogonal multiple access, interleaving multiple access or code division multiple access.
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| CN110061825B (en) * | 2019-04-24 | 2021-12-10 | 哈尔滨工业大学 | Method for optimizing pilot sequence based on observation matrix in uplink SCMA system |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1655477A (en) * | 2004-01-15 | 2005-08-17 | 三星电子株式会社 | Method for designing an uplink pilot signal and a method and a system for estimating a channel |
| CN1765093A (en) * | 2003-02-25 | 2006-04-26 | 高通股份有限公司 | Transmission scheme for a multi-antenna communication system using multi-carrier modulation |
| CN101026391A (en) * | 2007-03-30 | 2007-08-29 | 中兴通讯股份有限公司 | Multi communicty preambel detecting method and device |
| CN101208874A (en) * | 2005-03-07 | 2008-06-25 | 高通股份有限公司 | Pilot transmission and channel estimation for communication systems employing frequency division multiplexing |
| CN104869094A (en) * | 2015-04-29 | 2015-08-26 | 清华大学 | Upstream multiple access method combined with orthogonal multiple access and nonorthogonal multiple access |
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|---|---|---|---|---|
| US7889819B2 (en) * | 2002-10-04 | 2011-02-15 | Apurva Mody | Methods and systems for sampling frequency offset detection, correction and control for MIMO OFDM systems |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1765093A (en) * | 2003-02-25 | 2006-04-26 | 高通股份有限公司 | Transmission scheme for a multi-antenna communication system using multi-carrier modulation |
| CN1655477A (en) * | 2004-01-15 | 2005-08-17 | 三星电子株式会社 | Method for designing an uplink pilot signal and a method and a system for estimating a channel |
| CN101208874A (en) * | 2005-03-07 | 2008-06-25 | 高通股份有限公司 | Pilot transmission and channel estimation for communication systems employing frequency division multiplexing |
| CN101026391A (en) * | 2007-03-30 | 2007-08-29 | 中兴通讯股份有限公司 | Multi communicty preambel detecting method and device |
| CN104869094A (en) * | 2015-04-29 | 2015-08-26 | 清华大学 | Upstream multiple access method combined with orthogonal multiple access and nonorthogonal multiple access |
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