Methods and apparatus for multi-carrier communication systems with adaptive transmission and feedback

• US 8,027,367 B2
• Filed: 04/06/2010
• Issued: 09/27/2011
• Est. Priority Date: 02/13/2004
• Status: Active Grant

• Current Assignee: Neo Wireless LLC (f/k/a CFIP NCF LLC) (SoftBank Group Corp.)
• Original Assignee: Neocific Incorporated
• Inventors: Lo, Titus, Huang, Haiming, Li, Xiaodong, Li, Kemin
• Primary Examiner(s): Vu; Huy
• Assistant Examiner(s): Sekul; Maria
• Application Number:
  US12/755,313
• Publication Number:
  US 20100195609A1
• Time in Patent Office: 539 Days
• Field of Search: 370/330, 370/332, 370/350, 370/478, 370/485, 370/491, 370/500
• US Class Current: 370/491
• CPC Class Codes: H04B 7/0413 MIMO systems
• 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 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0029 Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling power control H04W52/04
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0073 Special arrangements for feedback channel
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• 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 5/0091 Signaling for the administration of the divided path
• CPC Class Codes: H04W 52/26 using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management

Abstract

An arrangement is disclosed where in a multi-carrier communication system, the modulation scheme, coding attributes, training pilots, and signal power may be adjusted to adapt to channel conditions in order to maximize the overall system capacity and spectral efficiency without wasting radio resources or compromising error probability performance, etc.

Claims

1. A communication method employed by a transmitter in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:

receiving information characterizing a first channel condition related to modulation and coding schemes (MCSs) and a second channel condition related to training pilot patterns for a telecommunications channel;

selecting, from a plurality of predetermined combinations of MCSs and training pilot patterns, a combination of an MCS and training pilot pattern for a transmission signal based on the received information characterizing the first and second channel conditions for the telecommunications channel, wherein;

the training pilot pattern represents a number of training pilot symbols, amplitudes and phases of the training pilot symbols, and locations of the training pilot symbols in time, frequency, or space;

the number of training pilot patterns varies with the associated MCS; and

at least one MCS has multiple training pilot patterns associated with it; and

transmitting the transmission signal in accordance with the selected MCS and training pilot pattern.

2. The method of claim 1, wherein the transmitter further:

generates a single index value to reflect the selected MCS and the selected training pilot pattern;

generates a control information signal which conveys the selected single index value; and

transmits the control information signal.

3. The method of claim 2, wherein the transmitter generates the single index value from a look-up table and wherein the look-up table includes the predetermined combinations of an MCS and a training pilot pattern employed by the transmitter.

4. The method of claim 1, further comprising:

selecting a rate matching scheme having repetition or puncturing for the transmission signal, the rate matching scheme selected to maintain equal packet sizes in the transmission signal when an MCS is used with different pilot patterns.

5. The method of claim 1, wherein the transmission signal is transmitted using a spatial processing scheme or multiple antenna techniques.

17. The method of claim 1, wherein the number of training pilot patterns that are associated with more frequently used MCSs is greater than the number of training pilot patterns that are associated with less frequently used MCSs.

18. The method of claim 1, further comprising receiving a probing sequence and estimating a channel profile in the time or frequency domain based on the received probing sequence.

6. A communication method employed by a receiver in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising:

receiving a signal;

measuring channel conditions, based on the received signal, wherein the measured channel conditions include;

signal strength, average signal to interference plus noise ratio (SINR), variance in time, variance in frequency, variance in space, bit error rate (BER), frame error rate (FER), mean square error (MSE), or any combination thereof; and

transmitting channel quality information (CQI) reflecting the measured channel conditions to a transmitter, wherein the CQI enables the transmitter to select a desired modulation and coding scheme (MCS) and a desired training pilot pattern out of a plurality of distinctive training pilot patterns that are associated with each MCS, wherein

each training pilot pattern represents a number of training pilot symbols, amplitudes, and phases of the training pilot symbols, and locations of the training pilot symbols in time, frequency, or space; and

the number of available training pilot patterns varies with the associated the number of training pilot patterns varies with the associated MCS and is based on the selected MCS; and

at least one MCS has multiple training pilot patterns associated with it.

7. The method of claim 6, wherein the receiver generates a CQI index value to reflect the CQI.

8. The method of claim 7, wherein the CQI index value is generated using a look-up table having sets of a modulation and coding scheme (MCS) and a training pilot pattern.

9. The method of claim 8, wherein the look-up table includes sets with the same MCS but different training pilot patterns.

10. The method of claim 7, wherein the CQI index value is transmitted to the transmitter using error protection coding.

11. The method of claim 10, wherein the CQI index value is Gray coded.

12. The method of claim 10, wherein more significant bits in the CQI index value are protected with stronger error protection codes.

13. The method of claim 6, wherein multiple antenna techniques are used to receive the signal.

14. The method of claim 6, wherein the transmitted CQI is user-based or subchannel-based.

15. The method of claim 6, wherein the received signal is from the transmitter.

16. The method of claim 6, wherein the received signal is from a common broadcast signal or a data signal targeted to another receiver.

19. The method of claim 6, wherein the number of training pilot patterns that are associated with more frequently used MCSs is greater than the number of training pilot patterns that are associated with less frequently used MCSs.

20. The method of claim 6, wherein the receiver further transmits a probing sequence that enables a transmitter to estimate a channel profile in the time or frequency domain based on the probing sequence.