SIGNAL TRANSMISSION METHOD AND FRAME STRUCTURE ADOPTED IN A TDD SYSTEM

• US 20110188414A1
• Filed: 10/23/2008
• Published: 08/04/2011
• Est. Priority Date: 10/28/2007
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Yu, Guanghui, Liang, Chunli, Dai, Bo, Xia, Shuqiang, Hao, Peng, Yu, Bin, Hu, Liujun
• Granted Patent: US 9,001,707 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04W 48/12 using downlink control channel

Abstract

A signal transmission method in a Time Division Duplex (TDD) system is disclosed. The method comprises following steps: within a time length of a half-frame of a radio frame, base station transmits signal on a downlink special time slot, thereafter does not transmit signal on a Guard Period (GP), and then receives signal on an uplink special time slot; all time lengths of other uplink or downlink normal time slots for transmitting signal are equal; the total time length of the downlink special time slot, the guard period and the uplink special time slot is integer times of the time length of an uplink or downlink normal time slot. In addition, a frame structure adopted in the TDD system which corresponds to the method is disclosed. The present invention makes it flexible to set the duration of the GP and it is guaranteed that, even if a synchronization signal adopts power promotion, it will not bring great interference to uplink reception of other base stations; in addition, the utilization efficiency of the system is improved.

Claims

1. A signal transmission method in a TDD system, comprising:

within a time length of a half-frame of a radio frame, a base station transmitting signals in a downlink special time slot, thereafter not transmitting signals in a guard period (GP), and then receiving signals in an uplink special time slot;

all time lengths of other uplink or downlink normal time slots for transmitting signals being equal;

the total time length of the downlink special time slot, the guard period and the uplink special time slot being integer times of the time length of one uplink or downlink normal time slot.

2. The method according to claim 1, wherein:

a primary synchronization (P-SCH) signal is transmitted in the first symbol of the downlink special time slot, and a secondary synchronization (S-SCH) signal is transmitted in the last symbol of the previous downlink time slot adjacent to the downlink special time slot;

or

the P-SCH signal and the S-SCH signal are transmitted in the first two symbols of the downlink special time slot;

or

the P-SCH signal and the S-SCH signal are transmitted in the last two symbols of the first downlink time slot in the half-frame.

3. The method according to claim 1, wherein:

an uplink random access signal is transmitted in one or more consecutive time slots of the uplink special time slot and the uplink normal time slot.

4. The method according to claim 3, wherein:

when a short random access channel (RACH) is adopted, the uplink random access signal is transmitted in the first two symbols of the uplink special time slot, or in the last two symbols of the uplink special time slot, or in start positions of other uplink time slots.

5. The method according to claim 1, wherein:

the time length of the downlink special time slot, that of the guard period (GP) and that of the uplink special time slot are set according to practical application occasions, and on the occasion when it is required to support larger coverage, the GP increases the length by occupying part of the time length of the downlink special time slot and that of the uplink special time slot, wherein growth granularity of the time length of the GP is symbol level, namely the time length of the GP being set is longer than that under the occasion which is only required to support a smaller coverage.

6. The method according to claim 1, wherein:

the number of the uplink and downlink normal time slots in the half-frame is 4, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 5, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 6, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 7, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 8, and the total time length of the downlink special time slot, the GP and the uplink special time slot is. 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 9, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 3 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 10, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 11, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 time of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 12, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 3 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 13, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 14, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 time of the time length of one normal time slot.

7. The method according to claim 1, wherein:

within the time length of the half-frame, the base station transmits signals in order in the first downlink normal time slot, in the second downlink normal time slot and in the downlink special time slot, thereafter does not transmit any signal in the GP, and then, receives signals in the uplink special time slot, and receives or transmits signals in the remaining 6 time slots according to uplink and downlink setting, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 2 times of the time length of one normal time slot.

8. The method according to claim 7, wherein when the TDD system coexists with a TD-SCDMA system,

if the proportion of downlink time slots and uplink time slots of the TD-SCDMA system is 2:

5, then;

if a normal cyclic prefix is adopted, the downlink special time slot includes 5 downlink symbols, and the time length is T_DL=356.8 us;

the time length of the GP is T_GP=142.72 us;

the uplink special time slot includes 7 uplink symbols, and the time length is T_UL=499.52 us;

if an extended cyclic prefix is adopted, the downlink special time slot includes 5 downlink symbols, and the time length is T_DL=417.6 us;

DL the time length of the GP is T_GP=83.34 us;

the uplink special time slot includes 6 uplink symbols, and the time length is T_UL=500.04 us;

if the proportion of downlink time slots and uplink time slots of the TD-SCDMA system is 3;

4, then;

if a normal cyclic prefix is adopted, the downlink special time slot includes 1 downlink symbol, and the time length is T_DL=71.36 us;

the time length of the GP is T_GP=142.72 us;

the uplink special time slot includes 11 uplink symbols, and the time length is T_UL=784.96 us;

if an extended cyclic prefix is adopted, the downlink special time slot includes 1 downlink symbol, and the time length is T_DL=83.34 us;

the time length of the GP is T_GP=166.68 us;

the uplink special time slot includes 9 uplink symbols, and the time length is T_UL=750.06 us;

if the proportion of downlink time slots and uplink time slots of the TD-SCDMA system is 4;

3, then;

if a normal cyclic prefix is adopted, the downlink special time slot includes 10 downlink symbols, and the time length is T_DL=713.6 us;

the time length of the GP is T_GP=142.72 us;

the uplink special time slot includes 2 uplink symbols, and the time length is T_UL=142.72 us;

if an extended cyclic prefix is adopted, the downlink special time slot includes 9 downlink symbols, and the time length is T_DL=750.06 us;

the time length of the GP is T_GP=83.34 us;

the uplink special time slot includes 2 uplink symbols, and the time length is T_UL=166.68 us;

if the proportion of downlink time slots and uplink time slots of the TD-SCDMA system is 5;

2, then;

if a normal cyclic prefix is adopted, the downlink special time slot includes 6 downlink symbols, and the time length is T_DL=428.64 us;

the time length of the GP is T_GP=142.72 us;

the uplink special time slot includes 6 uplink symbols, and the time length is T_UL=428.64 us;

if an extended cyclic prefix is adopted, the downlink special time slot includes 5 downlink symbols, and the time length is T_DL=417.6 us;

the time length of the GP is T_GP=166.68 us;

the uplink special time slot includes 5 uplink symbols, and the time length is T_UL=417.6 us;

if the proportion of downlink time slots and uplink time slots of the TD-SCDMA system is 6;

1, then;

if a normal cyclic prefix is adopted, the downlink special time slot includes 1 downlink symbol, and the time length is T_DL=71.36 us;

the time length of the GP is T_GP=142.72 us;

the uplink special time slot includes 11 uplink symbols, and the time length is T_UL=784.96 us;

if an extended cyclic prefix is adopted, the downlink special time slot includes 1 downlink symbol, and the time length is T_DL=83.34 us;

the time length of the GP is T_GP=166.68 us;

the uplink special time slot includes 9 uplink symbols, and the time length is T_UL=750.06 us;

or the parameter settings of the downlink special time slot, the GP and the uplink special time slot that correspond to the above-mentioned various proportions are applied when the TDD system and the TD-SCDMA system do not coexist.

9. The method according to claim 1, wherein when the TDD system does not coexist with a TD-SCDMA system:

if a normal cyclic prefix is adopted, the time length of the downlink special time slot is T_DL=71 us, in which 1 downlink symbol is included;

the time length of the GP is T_GP=929 us, equaling to the time length of 13 symbols;

the time length of the uplink special time slot is T_UL=0 us;

or

if an extended cyclic prefix is adopted, the time length of the downlink special time slot is T_DL=83 us, in which 1 downlink symbol is included;

the time length of the GP is T_GP=917 us, equaling to the time length of 11 symbols;

the time length of the uplink special time slot is T_UL=0 us;

under the above two circumstances, the total time length of the downlink special time slot and the GP equals to the time length of two normal time slots, and the uplink random access signal is transmitted in one or more consecutive uplink normal time slots.

10. The method according to claim 2, wherein the symbols included in the uplink time slot and/or downlink time slot are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

19. The method according to claim 4, wherein the symbols included in the uplink time slot and/or downlink time slot are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

20. The method according to claim 5, wherein the symbols included in the uplink time slot and/or downlink time slot are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

21. The method according to claim 8, wherein the symbols included in the uplink time slot and/or downlink time slot are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

22. The method according to claim 9, wherein the symbols included in the uplink time slot and/or downlink time slot are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

11. A frame structure adopted in a TDD system, in which a radio frame including two half-frames of equal length, wherein each of the half-frames further including one downlink special time slot, one guard period (GP), one uplink special time slot, and a plurality of uplink and downlink normal time slots of equal length, and the total time length of the downlink special time slot, the guard period and the uplink special time slot being integer times of the time length of one uplink or downlink normal time slot.

12. The frame structure according to claim 11, wherein:

the number of the uplink and downlink normal time slots in the half-frame is 4, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 5, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 6, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 7, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 8, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 9, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 or 3 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 10, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 11, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 time of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 12, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 3 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 13, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 2 times of the time length of one normal time slot;

or

the number of the uplink and downlink normal time slots in the half-frame is 14, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 1 time of the time length of one normal time slot.

13. The frame structure according to claim 11, wherein:

the half-frame includes two downlink normal time slots, one downlink special time slot, the GP, one uplink special time slot, and 6 uplink and/or downlink normal time slots in sequence, and the total time length of the downlink special time slot, the GP and the uplink special time slot is 2 times of the time length of one normal time slot.

14. The frame structure according to claim 13, wherein:

if the downlink special time slot and the uplink special time slot adopt a normal cyclic prefix, the downlink special time slot includes 5 downlink symbols, and the time length is T_DL=356.8 us;

the GP includes 2 symbols, and the time length is T_GP=142.72 us;

the uplink special time slot includes 7 uplink symbols, and the time length is T_DL=499.52 us;

or

if the downlink special time slot and the uplink special time slot adopt an extended cyclic prefix, the downlink special time slot includes 5 downlink symbols, and the time length is T_DL=417.6 us;

the GP includes 1 symbol, and the time length is T_GP=83.34 us;

the uplink special time slot includes 6 uplink symbols, and the time length is T_UL=500.04 us;

or

if the downlink special time slot and the uplink special time slot adopt a normal cyclic prefix, the downlink special time slot includes 1 downlink symbol, and the time length is T_DL=71.36 us;

the GP includes 2 symbols, and the time length is T_GP=142.72 us;

the uplink special time slot includes 11 uplink symbols, and the time length is T_DL=784.96 us;

or

if the downlink special time slot and the uplink special time slot adopt an extended cyclic prefix, the downlink special time slot includes 1 downlink symbol, and the time length is T_DL=83.34 us;

the GP includes 2 symbols, and the time length is T_GP=166.68 us;

the uplink special time slot includes 9 uplink symbols, and the time length is T_UL=750.06 us;

or

if the downlink special time slot and the uplink special time slot adopt a normal cyclic prefix, the downlink special time slot includes 10 downlink symbols, and the time length is T_DL=713.6 us;

the GP includes 2 symbols, and the time length is T_GP=142.72 us;

the uplink special time slot includes 2 uplink symbols, and the time length is T_UL=142.72 us;

or

if the downlink special time slot and the uplink special time slot adopt an extended cyclic prefix, the downlink special time slot includes 9 downlink symbols, and the time length is T_DL=750.06 us;

the GP includes 1 symbol, and the time length is T_GP=83.34 us;

the uplink special time slot includes 2 uplink symbols, and the time length is T_UL=166.68 us;

or

if the downlink special time slot and the uplink special time slot adopt a normal cyclic prefix, the downlink special time slot includes 6 downlink symbols, and the time length is T_DL=428.64 us;

the GP includes 2 symbols, and the time length is T_GP=142.72 us;

the uplink special time slot includes 6 uplink symbols, and the time length is T_UL=428.64 us;

or

if the downlink special time slot and the uplink special time slot adopt an extended cyclic prefix, the downlink special time slot includes 5 downlink symbols, and the time length is T_DL=417.6 us;

the GP includes 2 symbols, and the time length is T_GP=166.68 us;

the uplink special time slot includes 5 uplink symbols, and the time length is T_UL=417.6 us;

or

if the downlink special time slot and the uplink special time slot adopt a normal cyclic prefix, the downlink special time slot includes 1 downlink symbol, and the time length is T_DL=71.36 us;

the GP includes 2 symbols, and the time length is T_GP=142.72 us;

the uplink special time slot includes 11 uplink symbols, and the time length is T_UL=784.96 us;

or

if the downlink special time slot and the uplink special time slot adopt an extended cyclic prefix, the downlink special time slot includes 1 downlink symbol, and the time length is T_DL=83.34 us;

the GP includes 2 symbols, and the time length is T_GP=166.68 us;

the uplink special time slot includes 9 uplink symbols, and the time length is T_UL=750.06 us.

15. The frame structure according to claim 13, wherein:

as to the 6 normal time slots following the uplink special time slot, 2 or 4 uplink normal time slots are set first, then one uplink-downlink switch point is set, and then 4 or 2 downlink normal time slots are set;

or all the 6 normal time slots following the uplink special time slot are set to be uplink normal time slots.

16. The frame structure according to claim 11, wherein:

a primary synchronization (P-SCH)signal is transmitted in the first symbol of the downlink special time slot, while a secondary synchronization (S-SCH) signal is transmitted in the last symbol of the downlink time slot that is adjacent to the downlink special time slot, or the P-SCH signal and the S-SCH signal are transmitted in the first two symbols of the downlink special time slot, or the P-SCH signal and the S-SCH signal are transmitted in the last two symbols of the first downlink time slot.

17. The frame structure according to claim 11, wherein:

an uplink random access signal is transmitted in one or more consecutive time slots of the uplink special time slot and the uplink normal time slot, when a short random access channel (RACH) is adopted, the uplink random access signal is transmitted in the first two symbols of the uplink special time slot, or in the last two symbols of the uplink special time slot, or in start positions of other uplink time slots.

18. The frame structure according to claim 14, wherein the symbols included in the uplink time slot and/or downlink time slot are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

23. The frame structure according to claim 16, wherein the symbols included in the uplink time slot and/or downlink time slot are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

24. The frame structure according to claim 17, wherein the symbols included in the uplink time slot and/or downlink time slot are Orthogonal Frequency Division Multiplexing (OFDM) symbols.