Pilot designing method in an uplink OFDMA system

• US 20050243939A1
• Filed: 03/11/2005
• Published: 11/03/2005
• Est. Priority Date: 03/11/2004
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Original Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Inventors: Park, Hong-Sun, Jung, Young-Ho, Nam, Seung-Hoon, Lee, Yong-Hoon, Hwang, Chan-Soo, Chung, Jae-Hak
• Granted Patent: US 7,710,918 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0232 by interpolation between sounding signals
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

A pilot designing method in an uplink OFDMA system is provided. In the uplink OFDMA system, communications are carried out in a frame divided into time-frequency lattices, and each time-frequency lattice includes a plurality of data symbol periods and a plurality of pilot symbol periods intermittently arranged with respect to the data symbol periods. The frame is divided into a plurality of blocks. The blocks are allocated to the terminals. A predetermined allocated pilot time-frequency lattice is shared between adjacent terminals.

Claims

1. A pilot designing method in an uplink orthogonal frequency division multiple access (OFDMA) system where communications are carried out in a frame divided into time-frequency lattices, each time-frequency lattice including a plurality of data symbol periods and a plurality of pilot symbol periods intermittently arranged with respect to the data symbol periods, comprising the steps of:

dividing the frame into a plurality of blocks;

assigning the blocks to the terminals; and

sharing a predetermined allocated pilot time-frequency lattice between adjacent terminals.

2. The pilot designing method of claim 1, wherein the step of sharing the time-frequency lattice comprises inserting a pilot signal of a predetermined terminal and a pilot signal of an adjacent terminal in at least one pilot time-frequency lattice of the pilot symbol period allocated to a predetermined terminal.

3. The pilot designing method of claim 2, wherein the pilot signal of the predetermined terminal is orthogonal to the pilot signal of the adjacent terminal.

4. The pilot designing method of claim 1, wherein the step of sharing the time-frequency lattice comprises inserting only the pilot signal of an adjacent terminal in one of at least two pilot time-frequency lattices of the pilot symbol periods allocated to a predetermined terminal.

5. A data transmitting method in an uplink orthogonal frequency division multiple access (OFDMA) system where, for communication, a frame having time-frequency lattices is divided into a plurality of blocks, the blocks being allocated to the terminals, each time-frequency lattice including a plurality of data symbol periods and a plurality of pilot symbol periods intermittently arranged with respect to the data symbol periods, comprising the steps of:

arranging data signals and pilot signals of each terminal in the data symbol periods and the pilot symbol periods, respectively, of a block allocated to the terminal;

generating a transmission frame by inserting pilot signals of the terminal in predetermined pilot time-frequency lattices of an adjacent block allocated to a different terminal; and

transmitting the transmission frame.

6. A data transmitting method in an uplink orthogonal frequency division multiple access (OFDMA) communication system where a frame having time-frequency lattices is divided into a plurality of blocks, the blocks being allocated to the terminals, each time-frequency lattice including a plurality of data symbol periods and a plurality of pilot symbol periods intermittently arranged with respect to the data symbol periods, comprising the steps of:

arranging data signals and pilot signals of each terminal in the data symbol periods and the pilot symbol periods, respectively of a block allocated to the terminal;

emptying one of at least two time-frequency lattices of the pilot symbol period of the terminal, for filling a pilot signal of a different terminal in the empty time-frequency lattice;

generating a transmission frame by inserting a pilot signal of the terminal in an empty pilot time-frequency lattice among at least two pilot time-frequency lattices of an adjacent block allocated to the different terminal; and

transmitting the transmission frame.

7. A channel estimation method in an uplink orthogonal frequency division multiple access (OFDMA) communication system where a frame having time-frequency lattices is divided into a plurality of blocks, the blocks being allocated to the terminals, each time-frequency lattice including a plurality of data symbol periods and a plurality of pilot symbol periods intermittently arranged with respect to the data symbol periods, comprising the steps of:

receiving a frame with time-frequency lattices shared between adjacent blocks; and

estimating a channel of each of the terminals using a pilot signal included in a time-frequency lattice shared with an adjacent block allocated to a different terminal.

8. A channel estimation method in an uplink orthogonal frequency division multiple access (OFDMA) communication system where a frame having time-frequency lattices is divided into a plurality of blocks, the blocks being allocated to the terminals, each time-frequency lattice including a plurality of data symbol periods and a plurality of pilot symbol periods intermittently arranged with respect to the data symbol periods, comprising the steps of:

receiving a frame with time-frequency lattices which are exchanged between adjacent blocks; and

estimating a channel of each of the terminals using a pilot signal included in a time-frequency lattice exchanged from an adjacent block allocated to a different terminal.

9. A pilot designing method in an uplink orthogonal frequency division multiple access (OFDMA) system where communications are carried out in a frame divided into time-frequency lattices, each time-frequency lattice being identified by frequency-axis subcarrier indexes and time-axis symbol period indexes and including a plurality of intermittently arranged pilot subcarriers, comprising the steps of:

dividing the frame into transport blocks of a predetermined size and allocating the transport blocks to terminals; and

sharing pilot subcarriers of adjacent transport blocks allocated to different terminals in at least one symbol period.

10. The pilot designing method of claim 9, wherein the pilot subcarriers are shifted to other subcarrier indexes at predetermined symbol period intervals.

11. The pilot designing method of claim 10, wherein a transport block allocated to each terminal is shared by at least two antennas of the terminal.

12. The pilot designing method of claim 11, wherein the antennas map orthogonal pilot signals to pilot subcarriers in the transport block.

13. The pilot designing method of claim 10, wherein a pilot subcarrier is shared by the different terminals for four symbol periods.

14. The pilot designing method of claim 13, wherein a transport block allocated to each terminal is shared by at least two antennas of the terminal.

15. The pilot designing method of claim 14, wherein the pilot subcarrier is selectively allocated to the two antennas of the terminal for two successive symbol periods.

16. The pilot designing method of claim 15, wherein a pilot signal is mapped to pilot subcarriers having different indexes in the transport block for different symbol periods.

17. The pilot designing method of claim 14, wherein the pilot subcarrier is allocated to the two antennas of the terminal for the same two successive symbol periods.

18. The pilot designing method of claim 17, wherein a pilot signal is mapped to pilot subcarriers having different indexes in the transport block for different symbol periods.

19. The pilot designing method of claim 18, wherein the pilot signals mapped to the two antennas of the terminal are orthogonal to each other.

20. The pilot designing method of claim 13, wherein the pilot subcarrier is selectively allocated to at least two antennas of the terminal for a different symbol period.

21. The pilot designing method of claim 20, wherein a pilot signal is mapped to pilot subcarriers having different indexes in the transport block for different symbol periods.

22. A pilot designing method in an uplink orthogonal frequency division multiple access (OFDMA) system where communications are carried out in a frame divided into time-frequency lattices, each time-frequency lattice being identified by frequency-axis subcarrier indexes and time-axis symbol period indexes and including a plurality of intermittently arranged pilot symbol periods, comprising the steps of:

dividing the frame into transport blocks of a predetermined size and allocating the transport blocks to terminals; and

sharing pilot symbol periods of adjacent transport blocks allocated to different terminals in at least one subcarrier.

23. The pilot designing method of claim 22, wherein a transport block allocated to each terminal is shared by at least two antennas of the terminal.

24. The pilot designing method of claim 23, wherein the antennas map orthogonal pilot signals to pilot symbol periods in the transport block.