CN105553523A - Distributed processing-based OFDM communication system - Google Patents

Abstract

A distributed processing-based OFDM communication system provided by the invention fully considers discreteness of period delay information, the distributed OFDM system can obtain more accurate channel state information, signal quality of the distributed OFDM system received by a user terminal in motion is improved, interference between terminals during multiplexing transmission of multiple user terminals can be effectively eliminated, and the forward data rate of the distributed OFDM system is improved.

Description

OFDM communication system based on distributed processing

Technical Field

The invention relates to the field of wireless communication, in particular to an OFDM communication system based on distributed processing.

Background

In recent years, with the development of mobile communication technology, although the supporting capability of the communication system for wireless communication services has been significantly improved, the user terminal has a higher expectation for high-speed and high-quality multimedia services. Therefore, in the research of the next generation mobile communication technology, higher requirements are also put on the aspects of spectrum efficiency, transmission rate, system throughput, cell edge performance, and the like.

The access mode of OFDM enables the information of user terminals in a cell to be carried on different subcarriers which are orthogonal to each other, thereby effectively avoiding the multiple access interference among the user terminals in the cell, but the interference among the cells can not be inhibited. For the cell edge user terminals, the useful signal intensity is small, and the interference signal intensity from the adjacent cell is large, which limits the signal-to-noise ratio (SINR) of the cell edge user terminals, resulting in the reduction of throughput, so that the edge user terminals cannot obtain satisfactory service quality, and the improvement of system performance and system fairness is severely restricted.

With the development of the distributed processing technology, the joint processing of the multiple enodebs in a dispersed form becomes possible, the operation processing efficiency of the whole system can be greatly improved, the spectrum resources of the whole system can be effectively integrated, and the distributed processing method has a wide development prospect.

However, for the system performing distributed processing, since the terminal continuously moves in the coverage area of a plurality of enodebs, especially at high speed, the signal transmission direction and phase delay of each eNodeB are rapidly and dynamically changed, which causes the overall Channel State Information (CSI) of the entire distributed processing system to deviate too much from the true value, thereby affecting the overall performance of the system.

Disclosure of Invention

The purpose of the invention is realized by the following technical scheme.

According to an embodiment of the present invention, an OFDM communication system based on distributed processing is provided, the system including: the system comprises a user terminal in a moving state, a plurality of eNodeBs (evolved node Bs) for executing distributed processing and a main processing node, wherein the eNodeBs are connected through the main processing node, and the main processing node and the user terminal share a precoding database; and the main processing node and the distributed eNodeB adopt an OFDM mode to carry out data transmission with the user terminal.

According to the embodiment of the invention, the main processing node firstly acquires the historical service information of each eNodeB; then determining a target needing to be dispersed; then calculating a configuration result of the discrete resolution value; and indicating the resolution value configuration result.

According to the embodiment of the invention, the moving user terminal firstly performs dispersion on the channel beam pointing information; then calculating period delay information and performing dispersion on the period delay information; the discrete information is then reported to the main processing node.

According to the embodiment of the present invention, the main processing node is further configured to finally acquire channel state information of the entire distributed system.

According to the embodiment of the present invention, the discretization of the channel beam pointing information by the moving user terminal specifically includes:

the pointing vector of the forward link from the ith eNodeB to the moving user terminal is h_iThe moving user terminal indicates according to the ith eNodeBResolution value number B of_iSearching and resolving power value number B from self pre-coding database_iCorresponding precoding set C_BiSet of precodes C_BiComprises 2^BiA user terminal according toObtaining the pointing vector information h of the forward link in the ith cell_iCorresponding discrete precoding c_iWhereinIs h_iConjugation transposition, | charging |)²As a square of absolute value, C ∈ C_BiRepresents the selection of one precoding c from the set of precodes; moving user terminals get precoding c_iThen, report the precoding c to the ith eNodeB via the reverse link_iThe identification code of (1).

According to the OFDM communication system based on distributed processing, the dispersion of the period delay information is fully considered, the distributed OFDM system can obtain more accurate channel state information, the signal quality of the mobile user terminal for receiving the distributed OFDM system is improved, the terminal interference during multi-user terminal multiplexing transmission can be effectively eliminated, and the forward data rate of the distributed OFDM system is improved.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 shows a schematic structural diagram of an OFDM communication system based on distributed processing according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

According to an embodiment of the present invention, an OFDM communication system based on distributed processing is provided, as shown in fig. 1, the system includes: a user terminal in moving state, a plurality of eNodeBs executing distributed processing, and a main processing node, wherein the number of the eNodeBs is N_bThe ith eNodeB has N_tiAn antenna, i 1_bEach eNodeB is connected through a main processing node, and the main processing node and the user terminal share a precoding database; and the main processing node and the distributed eNodeB adopt an OFDM mode to carry out data transmission with the user terminal.

The main processing node firstly acquires the historical service information of each eNodeB; then determining a target needing to be dispersed; then calculating a configuration result of the discrete resolution value; and indicating the resolution value configuration result;

the moving user terminal firstly performs dispersion on the channel beam pointing information; then calculating period delay information and performing dispersion on the period delay information; then reporting the discrete information to the main processing node;

and finally, the main processing node acquires the channel state information of the whole distributed system.

According to an embodiment of the present invention, the acquiring, by the main processing node, the historical service information of each eNodeB specifically includes:

N_bin one eNodeBThe ith eNodeB instructs the moving user terminal to measure the historical integrated weighted signal strength of the forward link from the ith eNodeB to the moving user terminali＝1,…,N_b(ii) a The moving user terminal integrates the above-mentioned historical weighted signal strength via the reverse linkIs reported to N_bThe ith eNodeB in the eNodeBs further integrates the received historical weighted signal strengthReporting to the main processing node; this step is repeated for all other enodebs until the primary processing node obtains all N' s_bHistorical comprehensive weighted signal strength reported by each eNodeB;

according to an embodiment of the present invention, the determining, by the master processing node, the target that needs to be discretized specifically includes:

according toCalculating to obtain N_bAn identification code m of an eNodeB which does not need to be subjected to periodic delay dispersion in each eNodeB, wherein j is 1_bOperation ∑ denotes a sum operationMeans reacting in i 1The largest identification code;

according to an embodiment of the present invention, the configuration result of the main processing node calculating the discrete resolution value specifically includes:

the master processing node is represented by the following equation:

$B_i={\[(N_{ti}-1){\log }_2\left(\frac{{\mathrm{\α}}_i^2}{{\mathrm{\Σ}}_{j=1}^{N_b}{\mathrm{\α}}_j^2}\right)-(N_{ti}-1){\log }_2\left(\mathrm{\λ}\right(N_{ti}-1\left)\right)\]}^{+}$

$B_{i,p}=\frac{1}{2}{\[{\log }_2(\frac{{\mathrm{\α}}_i^2}{{\mathrm{\Σ}}_{j=1}^{N_b}{\mathrm{\α}}_j^2}-{\left(\frac{{\mathrm{\α}}_i^2}{{\mathrm{\Σ}}_{j=1}^{N_b}{\mathrm{\α}}_j^2}\right)}^2)-{\log }_2\left(\frac{\mathrm{\λ}}{2}\right)\]}^{+}$

calculating the resolution value number B of the beam pointing information configured for the forward link from the discrete ith eNodeB to the user terminal_i，i＝1,...,N_bAnd calculating the resolution value number B of the periodic delay information configured for the forward link from the discrete ith eNodeB to the user terminal_i,p，i＝1,...,N_bI ≠ m, where λ satisfiesB is the total resolution value number of the user terminal discrete channel information designated in advance by the distributed OFDM system, [ x ]]⁺Denotes max (0, x) operation, B in mth cell_m,pIs 0;

according to an embodiment of the present invention, the indicating, by the master processing node, a resolution value configuration result specifically includes:

number of resolution values B to be configured by the main processing node_i、B_i,pIndicating to the ith eNodeB; the ith eNodeB then counts the resolution value B_i、B_i,pIndicating to the moving user terminal; and repeat this step for all other enodebs;

according to the embodiment of the present invention, the discretization of the channel beam pointing information by the moving user terminal specifically includes:

the pointing vector of the forward link from the ith eNodeB to the moving user terminal is h_iThe number of resolution values B indicated by the ith eNodeB for the moving user terminal_iSearching and dividing from self pre-coding databaseResolution value number B_iCorresponding precoding set C_BiSet of precodes C_BiComprises 2^BiA user terminal according toObtaining the pointing vector information h of the forward link in the ith cell_iCorresponding discrete precoding c_iWhereinIs h_iConjugation transposition, | charging |)²As a square of absolute value, C ∈ C_BiRepresents the selection of one precoding c from the set of precodes; moving user terminals get precoding c_iThen, report the precoding c to the ith eNodeB via the reverse link_iThe identification code of (a); the user terminal repeats the step for all other eNodeBs until the channel beam pointing information of all eNodeBs is dispersed;

according to the embodiment of the present invention, the calculating of the period delay information by the moving ue specifically includes:

the moving user terminal calculates the pre-code c after the directional channel of the forward link in the ith cell is dispersed_iAnd phase delay between channel pointing vectorsWherein agl (x) is a phase delay operation for calculating a complex number x, and then the moving user terminal calculates the period delay information between the moving user terminal and the mth eNodeBThe user terminal repeats the step for all other eNodeBs until the cycle delay information of all eNodeBs except the mth eNodeB is calculated;

according to the embodiment of the present invention, the discretization of the period delay information by the moving user terminal specifically includes:

user terminal computing in motionNumber of resolution values B according to the i eNodeB indication_i,pSearching and resolving power value number B from self pre-coding database_i,pCorresponding precoding set C_Bi,pIn which C is_Bi,pComprises 2^Bi,pPrecoding, by calculation, of moving user terminalsObtaining periodic delay information of forward link in ith cellCorresponding discrete precoding c_i,p(ii) a The user terminal repeats the step for all other eNodeBs until the periodic delay information of all eNodeBs except the mth eNodeB is dispersed; in the m cell_m,pIs 0;

according to the embodiment of the present invention, the reporting of the discrete information by the moving user terminal specifically includes:

the moving user terminal reports the discrete precoding c to the ith eNodeB through the reverse link_iAnd discrete precoding c_i，pThe corresponding identification code, then the ith eNodeB reports the received identification code to the main processing node;

according to the embodiment of the present invention, the step of the main processing node finally acquiring the channel state information of the entire distributed system specifically includes:

the main processing node receives the identification code reported by the ith eNodeB and passes through a precoding set C in a precoding database of the main processing node_BiFinding the corresponding precoding c_iAnd pre-encoding the set C in the database by itself_Bi,pFinding the corresponding precoding c_i,p(ii) a Finally, the main processing node obtains the channel state information of the whole distributed system

Wherein,representing a modulus of 1 and a phase of c_i,p1, N, is the imaginary number of (a)_b，i≠m。

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (5)

1. An OFDM communication system based on distributed processing, the system comprising: the system comprises a user terminal in a moving state, a plurality of eNodeBs (evolved node Bs) for executing distributed processing and a main processing node, wherein the eNodeBs are connected through the main processing node, and the main processing node and the user terminal share a precoding database; and the main processing node and the distributed eNodeB adopt an OFDM mode to carry out data transmission with the user terminal.

2. A system as claimed in claim 1, the main processing node first obtaining historical service information of each eNodeB; then determining a target needing to be dispersed; then calculating a configuration result of the discrete resolution value; and indicating the resolution value configuration result.

3. A system according to claim 2, wherein said moving user terminal first performs dispersion on channel beam pointing information; then calculating period delay information and performing dispersion on the period delay information; the discrete information is then reported to the main processing node.

4. A system as recited in claim 3, said primary processing node further configured to obtain channel state information for the entire distributed system.

5. The system of claim 4, wherein the discretization of the channel beam pointing information by the moving user terminal comprises:

the pointing vector of the forward link from the ith eNodeB to the moving user terminal is h_iThe number of resolution values B indicated by the ith eNodeB for the moving user terminal_iSearching and resolving power value number B from self pre-coding database_iCorresponding precoding set C_BiSet of precodes C_BiComprises 2^BiA user terminal according toObtaining the pointing vector information h of the forward link in the ith cell_iCorresponding discrete precoding c_iWhereinIs h_iConjugation transposition, | charging |)²As a square of absolute value, C ∈ C_BiRepresents the selection of one precoding c from the set of precodes; moving user terminals get precoding c_iThen, report the precoding c to the ith eNodeB via the reverse link_iThe identification code of (1).