Method and apparatus for decoding physical broadcast channel in time division duplexing system

1. A method for decoding a Physical Broadcast Channel (PBCH) in a Time Division Duplexing (TDD) system, comprising:

performing de-Multiple Input Multiple Output (MIMO) processing on received data frames respectively according to antenna modes supported by the TDD system and buffering the data frames;

descrambling the data frames which are buffered and subjected to the de-MIMO processing and a combining, in unit of frame, the data frames descrambled in respective antenna modes; and

decoding the data frames combined;

wherein the combining, in unit of frame, the data frames descrambled in respective antenna modes comprises:

sequencing all scrambling codes supported by the TDD system, descrambling current data frames by using respective scrambling codes and storing descrambled data frames into respective storage areas in sequence; and

descrambling, in a cyclic shift, each subsequently received data frame by using each scrambling code, and performing log-likelihood ratio (LLR) combination on data frames subsequently descrambled and corresponding descrambled data frames previously stored according to a sequence after the cyclic shift;

wherein before the LLR combination, when a last combined data frame is descrambled by a last scrambling code, all data frames in a corresponding storage area are deleted and currently descrambled data frames are stored into the corresponding storage area.

2. The method according to claim 1 , further comprising:

before performing de-MIMO processing on received data frames respectively according to antenna modes supported by the TDD system, acquiring frame border information of the TDD system and determining respective data frames in received data according to the frame border information.

3. The method according to claim 1 , further comprising:

when the data frames are still not correctly decoded while the number of the data frames combined exceeds a predetermined threshold, determining that the PBCH fails to be decoded successfully, wherein the threshold is greater than or equal to 2(T tti /T f )−1, T tti being a transmission time interval of the PBCH and T f being a length of a data frame.

4. The method according to claim 1 , wherein the antenna modes comprise at least one of following modes:

a single antenna mode, a dual antenna mode and a quad antenna mode.

5. The method according to claim 2 , wherein the antenna modes comprise at least one of following modes:

a single antenna mode, a dual antenna mode and a quad antenna mode.

6. The method according to claim 3 , wherein the antenna modes comprise at least one of following modes:

a single antenna mode, a dual antenna mode and a quad antenna mode.

7. An apparatus for decoding a Physical Broadcast Channel (PBCH) in a Time Division Duplexing (TDD) system, comprising: a de-Multiple Input Multiple Output (MIMO) unit, a descrambling and combining unit and a decoding unit, wherein:

the de-MIMO unit is configured to perform de-MIMO processing on received data frames respectively according to antenna modes supported by the TDD system and buffering the data frames;

the descrambling and combining unit is configured to descramble the data frames which are buffered and subjected to the de-MIMO processing, and combine, in unit of frame, the data frames descrambled in each antenna mode; and

the decoding unit is configured to decode the data frames combined,

wherein the descrambling and combining unit comprises a first descrambling subunit, a storage subunit, a second descrambling subunit and a combining subunit; wherein

the first descrambling subunit is configured to sequence all scrambling codes supported by the TDD system and descramble current data frames by using respective scrambling codes;

the storage subunit is configured to store the data frames descrambled by using the scrambling codes into respective storage areas according to a sequence of the scrambling codes;

the second descrambling subunit is configured to descramble, in a cycle shift, each subsequently received data frame by using each scrambling code; and

the combining subunit is configured to combine the data frames descrambled by the second descrambling subunit with corresponding descrambled data frames previously stored according to a sequence after the cyclic shift, wherein, before the combination, when a last combined data frame is descrambled by a last scrambling code, all data frames in a corresponding storage area are deleted and currently descrambled data frames are stored into the corresponding storage area.

8. The apparatus according to claim 7 , further comprising an acquiring unit and a first determining unit, wherein

the acquiring unit is configured to acquire frame border information of the TDD system; and

the first determining unit is configured to determine respective data frames in received data according to the frame border information.

9. The apparatus according to claim 7 , further comprising:

a second determining unit configured to, when the data frames are still not correctly decoded while the number of the data frames combined exceeds a predetermined threshold, determine that the PBCH fails to be decoded successfully, wherein the threshold is greater than or equal to 2(T tti/T f )−1, T tti being a transmission time interval of the PBCH and T f being a length of a data frame.

10. The apparatus according to claim 7 , wherein the combination is LLR combination or soft bit combination.

11. The apparatus according to claim 7 , wherein the antenna modes comprise at least one of following modes:

a single antenna mode, a dual antenna mode and a quad antenna mode.

12. The apparatus according to claim 8 , wherein the combination is LLR combination or soft bit combination.

13. The apparatus according to claim 9 , wherein the combination is LLR combination or soft bit combination.

14. The apparatus according to claim 8 , wherein the antenna modes comprise at least one of following modes:

a single antenna mode, a dual antenna mode and a quad antenna mode.

15. The apparatus according to claim 9 , wherein the antenna modes comprise at least one of following modes:

a single antenna mode, a dual antenna mode and a quad antenna mode.