CN101873204A

CN101873204A - CSI-RS (Channel Status Information-Reference Signal) pilot frequency mode design of OFDM (Orthogonal Frequency Division Multiplexing) system

Info

Publication number: CN101873204A
Application number: CN201010199399A
Authority: CN
Inventors: 张颂; 蒋屹新; 文红; 张高远; 任祥维
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2010-06-12
Filing date: 2010-06-12
Publication date: 2010-10-27

Abstract

The invention discloses two CSI-RS (Channel Status Information-Reference Signal) design methods in the presence of a single cell and three cells. In the first method, TDM (Time Division Multiplexing), FDM (Frequency Division Multiplexing) and CSM (Code Space Multiplexing) are combined together, and in the second method, the TDM, the FDM and CDM (Code Division Multiplexing) are combined. The two models simultaneously use a TDD (Time Division Duplex) mode and an FDD (Frequency Division Duplex) mode and can improve the overall performance of the system.

Description

The CSI-RS pilot frequency mode design of ofdm system

Technical field

The invention belongs to electronic technology field,, thereby particularly carry out the mobile radio system that channel estimating improves communication performance with the CSI-RS pilot tone as radio communication, mobile communication etc.

Background technology

Long Term Evolution (Long Term Evolution abbreviates LTE as) system is the essential planning of third generation partnership.When the LTE system adopts the regular circulation prefix, time slot comprise 7 length on/descending symbol, when the LTE system adopts extended cyclic prefix, time slot comprise 6 length on/descending symbol.A Resource Unit (Resource Element, abbreviate RE as) be a subcarrier in the OFDM symbol, and a downlink resource piece (Resource Block abbreviates RB as) is made of continuous 12 subcarriers and 7 continuous (in the time of extended cyclic prefix being 6) OFDM symbols.A Resource Unit is 180kHz on frequency domain, is a general time slots length on the time domain, when carrying out resource allocation, can be that base unit distributes with the Resource Block.

(Further Advancements for E-UTRA, LTE-Advanced) system is the evolution version of LTE Release-8 to senior Long Term Evolution.LTE-Advanced satisfies except needs or surpasses 3Gpp TR25.913: " all related needs of Requirements for EvolvedUTRA (E-UTRA) and Evolved UTRAN (E-UTRAN), also should meet or exceed the demand of the IMT-Advanced of ITU-R proposition.Wherein, the demand with LTE Release-8 backward compatibility is meant: the terminal of LTERelease-8 can be worked in the network of LTE-Advanced, and the terminal of LTE-Advanced can be worked in the network of LTERelease-8.

In the 56th meeting of in February, 2009 3GPP to LTE-Advanced clear and definite for supporting the application and the COMP of 8 antennas, under the use of technology such as double fluid Beamforming, the design basic framework of LTE-Advanced downlink reference signal (Way forward), to be defined as two types reference signal to the downlink reference signal of LTE-Advanced operation: towards the reference signal of PDSCH demodulation with towards channel condition information (channel status Information, abbreviate CSI as) reference signal that produces, and, reference signal towards the PDSCH demodulation sends based on layer, every layer of a kind of reference signal of correspondence, at present, in the LTE-Advanced system, the number of plies that can support is 8 at most.

Though the MIMO-OFDM technology can be resisted channel fading well, improve spectrum efficiency and message transmission quantity, but correspondingly also make system become more complicated, wherein channel is owing to the introducing of MIMO becomes the synthetic of many subchannel (its number is the product of number of transmit antennas and reception antenna number), again owing to the OFDM technology adopts the channel that becomes on frequency and the time bidimensional.Estimate that for effective channel comes the signal of receiving terminal is carried out channel detection, coherent detection or other purposes, we must know CSI.Obtaining of CSI need be estimated channel, R8 has stipulated to adopt the channel estimation methods based on pilot signal in the MIMO-OFDM system, promptly clocklike insert to send in the two-dimentional Resource Block of frequency time to receive reference signal that is the CSI-RS that two ends are all known.

Summary of the invention

The method for designing that the purpose of this invention is to provide the following two kinds of CSI-RS of situation of a kind of single subdistrict and three sub-districts.The influence that the design of CSI-RS is surveyed system channel is important, and the CSI-RS design also will satisfy the given resource limit of system simultaneously.This patent proposes two kinds of CSI-RS patterns respectively, shown in figure one according to the available resources of system.This pattern is applicable to that TDD (time-division) system also is applicable to FDD (frequency division) system.First method shown in figure one (a), combines TDM (time-division), FDM (frequency division) and CSM (sign indicating number divides) respectively, second kind, shown in figure one (b), respectively TDM, FDM and CDM is combined.

Fig. 1 is the situations of two kinds of patterns under eight antennas of single sub-district, and this pattern can be realized the power Boost of 6dB.Fig. 2 is the situations of two kinds of patterns under three sub-district eight antennas, and this two pattern can both be realized: reach the quadrature of three cell patterns by the displacement of time-domain and frequency domain, realize the minimum interference of each sub-district CSI.

Description of drawings

Fig. 1 (a) be under the single cell conditions of TDM+FDM+CSM pattern in the mapping of Physical Resource Block, R0-R3 represents that antenna port is the CSI-RS placement location of 0-3, R4-R7 represents that antenna port is the CSI-RS placement location of 4-7.

Fig. 1 (b) be under TDM+FDM+CSM pattern three cell conditions in the mapping of Physical Resource Block, red representative sub-district 1, green representative sub-district 2, blue representative sub-district 3; R0-R3 represents that antenna port is the CSI-RS placement location of 0-3, and R4-R7 represents that antenna port is the CSI-RS placement location of 4-7.

Fig. 2 (a) is in the mapping of Physical Resource Block under the single cell conditions of TDM+FDM+CDM pattern, R0-R1 represents that antenna port is the CSI-RS placement location of 0-1, R2-R3 represents that antenna port is the CSI-RS placement location of 2-3, R4-R5 represents that antenna port is the CSI-RS placement location of 4-5, and R6-R7 represents that antenna port is the CSI-RS placement location of 6-7.

Being mapped as at Physical Resource Block under Fig. 2 (b) TDM+FDM+CDM pattern three cell conditions: red representative sub-district 1, green representative sub-district 2, blue representative sub-district 3; R0-R1 represents that antenna port is the CSI-RS placement location of 0-1, and R2-R3 represents that antenna port is the CSI-RS placement location of 2-3, and R4-R5 represents that antenna port is the CSI-RS placement location of 4-5, and R6-R7 represents that antenna port is the CSI-RS placement location of 6-7.

Embodiment

System adopts the regular circulation prefix, described Physical Resource Block comprises 12 subcarriers, comprise 14 OFDM symbols in time domain, adopt TDM+FDM+CSM and TDM++FDM+CDM pattern to insert the CSI-RS pilot tone in the relevant position respectively according to accompanying drawing, at receiving terminal the pilot tone place is carried out channel estimating and detect quality of channel, to improve the performance of system.

Claims

1. the method for designing that the purpose of this invention is to provide the following two kinds of CSI-RS of situation of a kind of single subdistrict and three sub-districts.

First method combines TDM, FDM and CSM respectively, and second kind combines TDM, FDM and CDM respectively, this two kinds of model uses simultaneously and TDD and fdd mode, and can improve the overall performance of system.

2. according to claim 1, when system adopted the regular circulation prefix, described Physical Resource Block comprised 12 subcarriers, comprises 14 OFDM symbols in time domain, and then described method is as follows:

(1) being mapped as at Physical Resource Block: R0-R3 represents that antenna port is the CSI-RS position of 0-3 under the single cell conditions of TDM+FDM+CSM pattern, adopts FDM to be placed on the 1st, 4,7,10 subcarrier places of the 11st OFDM symbol; R4-R7 represents that antenna port is the CSI-RS position of 4-7, adopts FDM and TDM to be placed on the 3rd, 8 subcarrier of the 6th OFDM symbol and the 3rd, 8 subcarrier of the 14th OFDM symbol; R0, R1, R2, R3 and R4, R5, R6, R7 distinguish with CSM respectively simultaneously.

(2) being mapped as at Physical Resource Block: R0-R1 represents that antenna port is the CSI-RS position of 0-1 under the single cell conditions of TDM+FDM+CDM pattern, adopts FDM to be placed on the 1st, 2 subcarrier of the 11st OFDM symbol; R2-R3 represents that antenna port is the CSI-RS position of 2-3, adopts TDM to be placed on the 3rd subcarrier place of the 6th and the 14th OFDM symbol; R4-R5 represents that antenna port is the CSI-RS position of 4-5, adopts FDM to be placed on the 7th, 8 subcarrier of the 11st OFDM symbol; R6-R7 represents that antenna port is the CSI-RS position of 6-7, adopts TDM to be placed on the 10th subcarrier place of the 6th and the 14th OFDM symbol; R0 and R1, R2 and R3, R4 and R5, R6 and R7 distinguish with CDM respectively simultaneously.

(3) being mapped as at Physical Resource Block under TDM+FDM+CSM pattern three cell conditions: red representative sub-district 1, green representative sub-district 2, blue representative sub-district 3; R0-R3 represents that antenna port is the CSI-RS position of 0-3, and R4-R7 represents that antenna port is the CSI-RS position of 4-7; R0, R1, R2, R3 and R4, R5, R6, R7 distinguish with CSM respectively; The R0-R3 of sub-district 1 adopts FDM to be placed on the 1st, 4,7,10 subcarrier places of the 11st OFDM symbol, and R4-R7 adopts FDM and TDM to be placed on the 3rd, 8 subcarrier of the 6th OFDM symbol and the 3rd, 8 subcarrier of the 14th OFDM symbol; The R0-R3 of sub-district 2 adopts FDM to be placed on the 2nd, 5,8,11 subcarrier places of the 11st OFDM symbol, and R4-R7 adopts FDM and TDM to be placed on the 4th, 9 subcarrier of the 6th OFDM symbol and the 4th, 9 subcarrier of the 14th OFDM symbol; The R0-R3 of sub-district 3 adopts FDM to be placed on the 3rd, 6,9,12 subcarrier places of the 11st OFDM symbol, and R4-R7 adopts FDM and TDM to be placed on the 5th, 10 subcarrier of the 6th OFDM symbol and the 5th, 10 subcarrier of the 14th OFDM symbol.

(4) being mapped as at Physical Resource Block under TDM+FDM+CDM pattern three cell conditions: red representative sub-district 1, green representative sub-district 2, blue representative sub-district 3; R0-R1 represents that antenna port is the CSI-RS position of 0-1, and R2-R3 represents that antenna port is the CSI-RS position of 2-3, and R4-R5 represents that antenna port is the CSI-RS position of 4-5, and R6-R7 represents that antenna port is the CSI-RS position of 6-7; R0 and R1, R2 and R3, R4 and R5, R6 and R7 distinguish with CDM respectively; The R0-R1 of sub-district 1 adopts FDM to be placed on the 1st, 2 subcarrier of the 11st OFDM symbol; R2-R3 adopts TDM to be placed on the 3rd subcarrier place of the 6th and the 14th OFDM symbol; R4-R5 adopts FDM to be placed on the 7th, 8 subcarrier of the 11st OFDM symbol; R6-R7 adopts TDM to be placed on the 8th subcarrier place of the 6th and the 14th OFDM symbol; The R0-R1 of sub-district 2 adopts FDM to be placed on the 3rd, 4 subcarrier of the 11st OFDM symbol; R2-R3 adopts TDM to be placed on the 4th subcarrier place of the 6th and the 14th OFDM symbol; R4-R5 adopts FDM to be placed on the 9th, 10 subcarrier of the 11st OFDM symbol; R6-R7 adopts TDM to be placed on the 9th subcarrier place of the 6th and the 14th OFDM symbol; The R0-R1 of sub-district 3 adopts FDM to be placed on the 5th, 6 subcarrier of the 11st OFDM symbol; R2-R3 adopts TDM to be placed on the 5th subcarrier place of the 6th and the 14th OFDM symbol; R4-R5 adopts FDM to be placed on the 11st, 12 subcarrier of the 11st OFDM symbol; R6-R7 adopts TDM to be placed on the 10th subcarrier place of the 6th and the 14th OFDM symbol.