Wireless communication methods, systems, and signal structures

• US 7,876,840 B2
• Filed: 12/15/2006
• Issued: 01/25/2011
• Est. Priority Date: 04/02/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Tong, Wen, Ma, Jianglei, Jia, Ming, Zhu, Peiying
• Primary Examiner(s): Ahn, Sam K
• Application Number:
  US11/639,191
• Publication Number:
  US 20070105508A1
• Time in Patent Office: 1,502 Days
• Field of Search: 375/260, 375/267, 375/299, 375/347, 375/349, 700/53, 455/101, 455132-141
• US Class Current: 375/260
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 2001/6908 using time hopping
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0667 of delayed versions of same signal using space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04J 11/00 Orthogonal multiplex systems, e.g. using WALSH codesH04J13/00 takes precedence
• CPC Class Codes: H04J 13/0074 Code shifting or hopping
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0069 Puncturing patterns
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/0625 Transmitter arrangements
• CPC Class Codes: H04L 1/0668 Orthogonal systems, e.g. using Alamouti codes
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04L 1/1867 : Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 25/0204 : of multiple channels
• CPC Class Codes: H04L 25/0226 : sounding signals per se
• CPC Class Codes: H04L 25/0242 : using matrix methods
• CPC Class Codes: H04L 27/2602 : Signal structure
• CPC Class Codes: H04L 27/2603 : Signal structure ensuring backward compatibility with legacy system
• CPC Class Codes: H04L 5/0023 : Time-frequency-space
• CPC Class Codes: H04L 5/0035 : Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0044 : allocation of payload
• CPC Class Codes: H04L 5/0048 : Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/006 : Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/1469 : using time-sharing

Abstract

Systems and methods for performing OFDM MIMO communications are provided. These include a frame structure; methods of combining various types of MIMO such as STTD and SM; sub-channel definitions; sub-FFT channel constructions; fast control channels; additional modulations; and group antenna transmit diversity; new incremental redundancy schemes.

Claims

1. A method of transmitting a time division duplexing (TDD) frame structure of a transmission signal from a transmitter to a receiver, the method comprising:

defining, by a network element in a communication network, a plurality of time slots each comprising at least two orthogonal frequency division multiplexing (OFDM) symbols;

defining, by the network element, at least one fixed switching point within the frame structure;

defining, by the network element, at least one flexible switching point within the frame structure, wherein at each fixed switching point within the frame structure, a predetermined one of uplink or downlink transmission is performed; and

at each flexible switching point within the frame structure, a direction of communications is optionally switched.

2. The method of claim 1 wherein all of the switching points are at slot boundaries.

3. The method of claim 1 wherein at least one of the flexible switching points is not on a slot boundary.

4. The method of claim 1 wherein each period of uplink transmission is delineated by a TTG (transmit transition gap) and a RTG (receive transition gap) that are collectively substantially equal in duration to an OFDM symbol pair, wherein for pairs of consecutive slots during which no TTG and RTG is necessary, an OFDM symbol pair is transmitted instead.

5. A multiple input multiple output (MIMO) OFDM transmitter adapted to implement the method of claim 1.

6. A method of transmitting a time division duplexing (TDD) frame structure of a transmission signal from a transmitter to a receiver, the method comprising:

defining, by a network element in a communication network, a plurality of TDD slots each comprising at least two orthogonal frequency division multiplexing (OFDM) symbols;

at TDD slot boundaries, defining, by the network element, at least one fixed switching point within the frame structure and at least one flexible switching point within the frame structure;

wherein at each fixed switching point within the frame structure, a predetermined one of uplink or downlink transmission is performed;

wherein at each flexible switching point within the frame structure, uplink or downlink transmission can be scheduled; and

wherein the fixed switching point(s) are common across a network, and the flexible switching point(s) are selected on a cell/beam specific basis.

7. The method of claim 6 further comprising:

transmitting the frame structure at each of a plurality of base stations forming a network such that the fixed switching point(s) are common across the network, and the flexible switching point(s) are selected on a cell/beam specific basis.

8. The method of claim 6 wherein each TDD slot comprises a plurality of pairs of OFDM symbols and a tail symbol, the method further comprising at each transition point performing one of:

if there is an DL/UL (downlink/uplink) switch scheduled at that transition point, separating the tail symbol into two parts, one serving as TTG (transmit transition gap), and the other serving as RTG (receive transition gap);

if there is no DL/UL switch scheduled at that transition point, using the tail symbol as a regular traffic OFDM symbol.

9. The method of claim 8 wherein using the tail symbol as a regular traffic OFDM symbol comprises combining the tail symbol with another tail symbol in an adjacent TDD slot to generate an OFDM symbol pair.

10. The method of claim 9 wherein each TDD frame has a duration of 10 ms.

11. The method of claim 10 wherein each TDD frame comprises five TDD slots each with a duration of 2 ms, and each consisting of 9 OFDM symbol pairs and one tail symbol.

12. The method of claim 11 wherein each pair of OFDM symbols is space time coded.

13. The method of claim 6 wherein the fixed switching points are at slot boundaries, and the flexible switching points are at slot boundaries or within specific slots.

14. A MIMO OFDM transmitter adapted to implement the method of claim 6.

15. An OFDM receiver adapted to process signals generated in accordance with claim 6.

16. An OFDM communications system adapted to implement the method of claim 6.

17. A method of transmitting a signal from a transmitter to a receiver, the method comprising:

defining, by a network element in a communication network, time division duplexing (TDD) slots each comprising a plurality of orthogonal frequency division multiplexing (OFDM) symbols for traffic and a tail symbol;

for at least some slots, using, by the network element, the tail symbol as a transmit/receive transmission guard (TTG) or receive/transmit transition guard (RTG) to facilitate switching between uplink and downlink transmission or vice versa;

allocating, by the network element, the tail symbol for traffic for at least one slot during which there is to be no switch between uplink and downlink transmission or vice versa.

18. The method of claim 17 wherein allocating the tail symbol for traffic comprises combining the tail symbol with another tail symbol in an adjacent TDD slot to generate an OFDM symbol pair.