Method and Device for Downlink Cooperation Retransmission in a Relay Station

• US 20120120865A1
• Filed: 03/23/2010
• Published: 05/17/2012
• Est. Priority Date: 05/04/2009
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Liang, Feng, Bi, Feng, Yang, Jin, Wu, Shuanshuan, Yuan, Ming
• Granted Patent: US 8,654,781 B2
• Time in Patent Office: Days
• US Class Current: 370/315
• CPC Class Codes: H04B 7/15542 Selecting at relay station its transmit and receive resources selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003
• CPC Class Codes: H04B 7/15592 Adapting at the relay station communication parameters for supporting cooperative relaying, i.e. transmission of the same data via direct - and relayed path cooperative diversity H04B7/024
• CPC Class Codes: H04L 1/0067 Rate matching H04L1/0013 and H04L1/08 take precedence
• CPC Class Codes: H04L 1/1893 Physical mapping arrangements physical resource mapping in general H04L5/00
• CPC Class Codes: H04L 2001/0097 Relays
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals

Abstract

The present invention discloses a method and apparatus for relay station downlink cooperative retransmission, wherein said method comprises: a relay station carrying out physical layer processing in advance on data which requires retransmitting according to a case that available wireless resources number for retransmitting data in a retransmission subframe is to be determined, generating corresponding Orthogonal Frequency Division Multiplexing (OFDM) signals, and monitoring a Physical Control Format Indicator Channel (PCFICH) of the retransmission subframe, and according to a monitoring result, selecting an OFDM signal which matches with the determined available wireless resources number from said OFDM signals to carry out retransmission transmitting.

Claims

1. A method for relay station downlink cooperative retransmission, comprising:

the relay station carrying out physical layer processing in advance on data which requires retransmitting according to a case that an available wireless resources number for retransmitting data in a retransmission subframe is to be determined, generating corresponding Orthogonal Frequency Division Multiplexing (OFDM) signals, and monitoring a Physical Control Format Indicator Channel (PCFICH) of the retransmission subframe, and according to a monitoring result, selecting an OFDM signal which matches with a determined available wireless resources number from said OFDM signals to carry out retransmission transmitting.

2. The method as claimed in claim 1, wherein the step of carrying out physical layer processing and generating OFDM signals comprises:

when the relay station is required to carry out the downlink cooperative retransmission, carrying out the physical layer processing on a Transport Block (TB) which requires retransmitting, and before carrying out rate matching on the TB which requires retransmitting or a Code Block (CB) obtained by sectioning this TB, obtaining an available bit number to be determined for retransmitting this TB; and

the relay station taking said available bit number to be determined for retransmitting this TB as an available bit number for retransmitting this TB, carrying out the rate matching on this TB or the CB obtained by sectioning this TB, and continuing to carry out the physical layer processing on the TB or CB for which the rate matching has been completed, and generating the OFDM signals;

wherein in the step of monitoring the PCFICH of the retransmission subframe, the relay station monitors the PCFICH of the retransmission subframe to obtain a determined occupied symbol number of a Physical Downlink Control Channel (PDCCH) in the retransmission subframe;

in the step of selecting the OFDM signal to carry out retransmission transmitting, regarding the TB which requires retransmitting, according to the obtained determined occupied symbol number of the PDCCH in the retransmission subframe, the relay station selects one OFDM signal which matches with the determined available wireless resources number for retransmitting the TB in retransmission subframe from the obtained OFDM signals generated by the TB which requires retransmitting, and retransmits the selected OFDM signal in the retransmission subframe.

3. The method as claimed in claim 2, wherein

in the step of obtaining the available bit number to be determined for retransmitting this TB, according to an occupied symbol number to be determined of the PDCCH in the retransmission subframe, a total available symbol number in the retransmission subframe, a sub-carrier number and a modulation order number allocated to the TB which requires retransmitting, and a total Resource Element (RE) number occupied by a pilot, a synchronization signal and a system broadcast message, the relay station obtains the available bit number to be determined in one or more cases of retransmitting this TB.

4. The method as claimed in claim 3, wherein

in the step of obtaining the available bit number to be determined for retransmitting this TB, when the occupied symbol number to be determined of the PDCCH in the retransmission subframe has N cases, in the kth case, a symbol number which will be occupied by the PDCCH in the retransmission subframe is N_S—

_PDCCH^(k), wherein 1≦

k≦

N, and N is a positive integer; and

the total available symbol number in the retransmission subframe is N<sub>S—

All</sub>, and an available symbol number to be determined N<sub>S—

U</sub>^(k) for retransmission in the retransmission subframe is obtained in a following way;

N<sub>S—

U</sub>^(k)=N<sub>S—

All</sub>−

N<sub>S—

PDCCH</sub>^(k);

at this time, the sub-carrier number and the modulation order number allocated to the TB which requires retransmitting are respectively and N<sub>C—

U</sub> and Q_m, the total RE number occupied by the pilot, the synchronization signal and the system broadcast message is N′

_RE, and then the available bit number to be determined N<sub>B—

U</sub>^(k) in the N cases of retransmitting this TB is obtained in a following way;

N<sub>B—

U</sub>^(k)=(N<sub>S—

U</sub>^(k)×

N<sub>C—

U</sub>−

N′

_RE)×

Q_m.

5. The method as claimed in claim 2, wherein

in the step of carrying out the rate matching, said relay station respectively takes the available bit number to be determined in each case as a total available bit number for retransmitting this TB to carry out the rate matching respectively, and correspondingly outputs one or more TBs or CBs for which the rate matching has been completed, and continues to carry out the physical layer processing until generating one or more OFDM signals.

6. The method as claimed in claim 2, wherein

in the step of selecting the OFDM signal to carry out retransmission transmitting, according to the determined occupied symbol number of the PDCCH in the retransmission subframe, the relay station further obtains a determined available symbol number for retransmitting this TB in the retransmission subframe, and according to said determined available symbol number for retransmitting this TB in the retransmission subframe, selects one OFDM signal which matches with the determined available wireless resources number for retransmitting the TB in retransmission subframe to carry out retransmission transmitting;

said determined available symbol number N′

<sub>S—

U</sub> for retransmitting this TB in the retransmission subframe is obtained in a following way;

N′

<sub>S—

U</sub>=N<sub>S—

All</sub>−

N′

<sub>S—

PDCCH</sub>,

wherein N<sub>S—

All</sub> is a total available symbol number in the retransmission subframe, and N′

<sub>S—

PDCCH</sub> is the determined occupied symbol number of the PDCCH in the retransmission PDCCH subframe.

7. The method as claimed in claim 2, wherein

in the step of selecting the OFDM signal to carry out retransmission transmitting, according to the determined occupied symbol number of the PDCCH in the retransmission subframe, the relay station further obtains a determined available symbol number for retransmitting this TB in the retransmission subframe, and further obtains a determined available bit number for retransmitting this TB, and according to said determined available bit number for retransmitting this TB, selects one OFDM signal which matches with the determined available wireless resources number for retransmitting the TB in retransmission subframe to carry out retransmission transmitting;

said determined available bit number for N′

<sub>B—

U</sub> for retransmitting this TB is obtained in a following way;

N′

<sub>B—

U</sub>=(N′

<sub>S—

U</sub>×

N<sub>C—

U</sub>−

N′

_RE)×

Q_m,

wherein N′

<sub>S—

U</sub> is the determined available symbol number for retransmitting this TB in the retransmission subframe, N<sub>C—

U</sub> is a sub-carrier number allocated to the TB which requires retransmitting, Q_m, is a modulation order number allocated to the TB which requires retransmitting, and N′

_RE is a total RE number occupied by a pilot, a synchronization signal and a system broadcast message.

8. The method as claimed in claim 1, wherein

after monitoring the PCFICH and before the retransmission transmitting, the relay station reserves a period as a guard interval, and the relay station does not carry out downlink receiving and downlink transmitting in the guard interval.

9. The method as claimed in claim 1, wherein

in the step of retransmission transmitting, a base station and the relay station retransmits said OFDM signal which matches with the determined available wireless resources number at the same time, or only the relay station retransmits the OFDM signal which matches with the determined available wireless resources number.

10. An apparatus for downlink cooperative retransmission, comprising a physical layer processing module, a monitoring module, and a selecting and transmitting module, wherein:

said physical layer processing module is configured to carry out physical layer processing in advance on data which requires retransmitting according to a case that an available wireless resources number for retransmitting data in a retransmission subframe is to be determined, and generate corresponding Orthogonal Frequency Division Multiplexing (OFDM) signals;

said monitoring module is configured to monitor a Physical Control Format Indicator Channel (PCFICH) of the retransmission subframe;

said selecting and transmitting module is connected with said physical layer processing module and the monitoring module respectively, and said selecting and transmitting module is configured to obtain OFDM signals generated by said physical layer processing module, and according to a monitoring result of said monitoring module, selecting an OFDM signal which matches with a determined available wireless resources number from said OFDM signals to carry out retransmission transmitting.

11. The apparatus as claimed in claim 10, wherein

said physical layer processing module comprises a first physical layer processing sub-module, a rate matching sub-module, and a second physical layer processing sub-module connected in sequence, and an obtaining sub-module connected with the rate matching sub-module;

said first physical layer processing sub-module is configured to carry out all or parts of steps of adding a Cyclic Redundancy Check (CRC) to a Transport Block (TB), Code Block (CB) sectioning and adding a CRC to the CB, and channel coding;

said obtaining sub-module is configured to obtain an available bit number to be determined for retransmitting this TB;

said rate matching sub-module is configured to take said available bit number to be determined for retransmitting this TB as an available bit number for retransmitting this TB, carrying out rate matching on this TB or the CB obtained by sectioning this TB which have been processed by the first physical layer processing sub-module;

said second physical layer processing sub-module is configured to carry out all or parts of steps of CBs concatenating, scrambling, modulating, layer mapping, pre-coding, and wireless resources mapping for TB or CB after the rate matching sub-module implements the rate matching, and generate the OFDM signals.

12. The apparatus as claimed in claim 10, wherein

said monitoring module is configured to monitor the PCFICH of the retransmission subframe to obtain a determined occupied symbol number of a Physical Downlink Control Channel (PDCCH) in the retransmission subframe;

said selecting and transmitting module is configured to regarding the TB which requires retransmitting, according to the determined occupied symbol number of the PDCCH in the retransmission subframe obtained by the monitoring module, select one OFDM signal which matches with the determined available wireless resources number for retransmitting the TB in the retransmission subframe from the OFDM signals generated by the TB which requires retransmitting obtained by the physical layer processing module, and retransmits the selected OFDM signal in the retransmission subframe.

13. The apparatus as claimed in claim 11, wherein

said obtaining sub-module is configured to according to an occupied symbol number to be determined of the PDCCH in the retransmission subframe, a total available symbol number in the retransmission subframe, a sub-carrier number and a modulation order number allocated to the TB which requires retransmitting, and a total RE number occupied by a pilot, a synchronization signal and a system broadcast message, obtain the available bit number to be determined in one or more cases of retransmitting this TB;

wherein when the occupied symbol number to be determined of the PDCCH in the retransmission subframe has N cases, in the kth case, the occupied symbol number to be determined of the PDCCH in the retransmission subframe is N<sub>S—

PDCCH</sub>^(k), wherein 1≦

k≦

N, and N is a positive integer; and

the total available symbol number in the retransmission subframe is N<sub>S—

All</sub>, and an available symbol number to be determined N<sub>S—

U</sub>^(k) for retransmission in the retransmission subframe is obtained by the obtaining sub-module in a following way;

N<sub>S—

U</sub>^(k)=N<sub>S—

All</sub>−

N<sub>S—

PDCCH</sub>^(k);

at this time, the sub-carrier number and the modulation order number allocated to the TB which requires retransmitting are respectively N<sub>C—

U</sub> and Q_m, the total RE number occupied by the pilot, the synchronization signal and the system broadcast message is N′

_RE, and then the available bit number to be determined N<sub>B—

U</sub>^(k) (1≦

k≦

N) in the N cases of retransmitting this TB is obtained by the obtaining sub-module in a following way;

N<sub>B—

U</sub>^(k)=(N<sub>S—

U</sub>^(k)×

N<sub>C—

U</sub>−

N′

_RE)×

Q_m.

14. The apparatus as claimed in claim 12, wherein

said selecting and transmitting module is also configured to according to the determined occupied symbol number of the PDCCH in the retransmission subframe, further obtain a determined available symbol number for retransmitting this TB in the retransmission subframe, and according to said determined available symbol number for retransmitting this TB in the retransmission subframe, select one OFDM signal which matches with the determined available wireless resources number for retransmitting the TB in retransmission subframe to carry out retransmission transmitting;

or according to the determined occupied symbol number of the PDCCH in the retransmission subframe, further obtain the determined available symbol number for retransmitting this TB in the retransmission subframe, and further obtain a determined available bit number for retransmitting this TB, and according to said determined available bit number for retransmitting this TB, select one OFDM signal which matches with the determined available wireless resources number for retransmitting the TB in retransmission subframe to carry out retransmission transmitting.

15. A relay station, and said relay station comprising said apparatus for downlink cooperative retransmission in claim 10.

16. The apparatus as claimed in claim 11, wherein

said monitoring module is configured to monitor the PCFICH of the retransmission subframe to obtain a determined occupied symbol number of a Physical Downlink Control Channel (PDCCH) in the retransmission subframe;

said selecting and transmitting module is configured to regarding the TB which requires retransmitting, according to the determined occupied symbol number of the PDCCH in the retransmission subframe obtained by the monitoring module, select one OFDM signal which matches with the determined available wireless resources number for retransmitting the TB in the retransmission subframe from the OFDM signals generated by the TB which requires retransmitting obtained by the physical layer processing module, and retransmits the selected OFDM signal in the retransmission subframe.

17. A relay station, and said relay station comprising said apparatus for downlink cooperative retransmission in claim 11.

18. A relay station, and said relay station comprising said apparatus for downlink cooperative retransmission in claim 12.

19. A relay station, and said relay station comprising said apparatus for downlink cooperative retransmission in claim 13.

20. A relay station, and said relay station comprising said apparatus for downlink cooperative retransmission in claim 14.