OFDMA with adaptive subcarrier-cluster configuration and selective loading

• US 8,036,199 B2
• Filed: 03/29/2010
• Issued: 10/11/2011
• Est. Priority Date: 12/15/2000
• Status: Expired due to Fees

• Current Assignee: Adaptix, Inc. (Acacia Research Corporation)
• Original Assignee: Adaptix, Inc. (Acacia Research Corporation)
• Inventors: Zhang, Wenzhong, Li, Xiaodong, Liu, Hui, Li, Kemin
• Primary Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US12/748,781
• Publication Number:
  US 20100238833A1
• Time in Patent Office: 561 Days
• Field of Search: 370203-204, 370/206, 370/208, 370/210, 370328-334, 370/341, 370343-345, 370/350, 370252-253, 370/338, 370436-437, 370443-444, 370/480, 455/63.1, 455/67.11, 455/67.13, 455/509, 455512-513, 455/517, 455/550.1, 455/556.2, 455/561, 455/69, 455/70, 455/101, 455/418, 455/500, 455524-526, 375260-261, 375/264, 375/267, 375331-332, 375346-349, 375/299, 375/347
• US Class Current: 370/344
• CPC Class Codes: H04B 17/336 Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04J 11/00 Orthogonal multiplex systems, e.g. using WALSH codesH04J13/00 takes precedence
• CPC Class Codes: H04J 11/003 at the transmitter transmission to multiple receive units in multiple input multiple output [MIMO] H04B7/0452; transmit antenna weighting H04B7/0615
• CPC Class Codes: H04J 11/005 of intercell interference
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0005 applied to payload information
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0011 applied to payload information
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0079 Formats for control data H04L1/16 takes precedence; training sequences H04L25/00 and H04L27/00
• CPC Class Codes: H04L 1/04 using frequency diversity
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/0035 : Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0037 : Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0042 : intra-user or intra-terminal allocation
• 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 5/005 : of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/006 : Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0064 : Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0073 : Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04L 5/0082 : at predetermined intervals
• CPC Class Codes: H04L 5/0094 : Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04L 5/023 : Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04W 24/08 : Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 72/04 : Wireless resource allocation
• CPC Class Codes: H04W 72/0453 : Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/20 : Control channels or signalling for resource management
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/541 : using the level of interference
• CPC Class Codes: H04W 72/542 : using measured or perceived quality
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02

Abstract

A method and apparatus for allocating subcarriers in an orthogonal frequency division multiple access (OFDMA) system is described. In one embodiment, the method comprises allocating at least one diversity cluster of subcarriers to a first subscriber and allocating at least one coherence cluster to a second subscriber.

Claims

1. A method for estimating interference using received pilot symbols, said method comprising:

receiving, at a subscriber station, pilot symbols from at least two base stations;

estimating, at said subscriber station, a channel response based, at least on, said received pilot symbols; and

estimating, at said subscriber station, a first interference level in a data period using said estimated channel response.

2. The method of claim 1 further comprising:

calculating a second interference level in a pilot period based, at least on, said received pilot symbols;

determining an order for two or more clusters of subcarriers using at least said first interference level and said second interference level; and

selecting at least one cluster based, at least, on said determined order and one or more predetermined performance criteria.

3. The method of claim 2 further comprising:

predicting an available data rate for said ordered clusters.

4. The method of claim 3 wherein said predicting comprises:

obtaining said data rate information from a table, wherein said table stores a desired transmission rate associated with an interference level.

5. A method for determining subcarrier energy levels based on received pilot symbols, said method comprising:

receiving pilot symbols from at least two base stations;

determining a first energy level of one or more clusters of subcarriers by performing energy detection for said one or more clusters based, at least, on said received pilot symbols;

determining a second energy level of said one or more clusters of subcarriers by performing energy detection for said one or more clusters during a data period; and

calculating an energy difference between the first energy level and the second energy level.

6. The method of claim 5 further comprising:

determining an order for two or more clusters using at least said calculated energy difference between the first and second energy levels; and

selecting at least one cluster based, at least, on said determined order and one or more predetermined performance criteria.

7. The method of claim 5 wherein calculating said energy difference between the first and second energy levels comprises:

comparing the signal power of a cluster based on said received pilot symbols with the signal power of the cluster during the data period.

8. The method of claim 5 wherein calculating said difference in the first and second energy levels comprises:

comparing the energy of one or more observed samples based on said received pilot symbols with the energy of said one or more observed samples during the data period, wherein said comparing is performed for subcarriers in said one or more clusters; and

summing the comparison results for each subcarrier.

9. A subscriber station comprising:

a processor for determining a first energy level of one or more clusters of subcarriers by performing energy detection for the one or more clusters based on received pilot symbols from at least two base stations;

determining a second energy level of said one or more clusters by performing energy detection for said one or more clusters during a data period; and

calculating a difference in the first energy level and the second energy level.

10. The subscriber station of claim 9 wherein said processor:

further determines an order for two or more clusters using at least said calculated energy difference between the first and second energy levels; and

wherein said processor selects at least one cluster based, at least, on said determined order and one or more predetermined performance criteria.

11. The subscriber station of claim 9 wherein said processor compares the signal power of a cluster based on said received pilot symbols with the signal power of the cluster during the data period.

12. The subscriber station of claim 9 wherein said processor compares the energy of one or more observed samples based on said received pilot symbols with the energy of said one or more observed samples during the data period, wherein said comparing is performed for subcarriers in said one or more clusters;

and

sums the comparison results for each subcarrier.

13. A subscriber station comprising:

a processor estimating a channel response based, at least on, received pilot symbols from at least two base stations; and

estimating a first interference level in a data period using said estimated channel response.

14. The subscriber station of claim 13 wherein said processor:

calculates a second interference level in a pilot period based, at least on, said received pilot symbols;

determines an order for two or more clusters using at least said first interference level and said second interference level; and

selects at least one cluster based, at least, on said determined order and one or more predetermined performance criteria.

15. The subscriber station of claim 14 wherein said processor:

predicts an available data rate for said ordered clusters.

16. The subscriber station of claim 15 wherein said processor obtains said data rate information from a table, wherein said table stores a desired transmission rate associated with an interference level.

17. A subscriber station comprising:

a processor determining a first energy level of one or more clusters of subcarriers by performing energy detection for the one or more clusters based on received pilot symbols from at least two base stations;

determining a second energy level of said one or more clusters by performing energy detection for said one or more clusters during a data period; and

calculating a difference in the first energy level and the second energy level.

18. The subscriber station of claim 17 further comprising wherein said processor further:

determines an order for two or more clusters using at least said calculated energy difference between the first and second energy levels; and

wherein said processor selects at least one cluster based, at least, on said determined order and one or more predetermined performance criteria.

19. The subscriber station of claim 17 wherein said processor compares the signal power of a cluster based on said received pilot symbols with the signal power of the cluster during the data period.

20. The subscriber station of claim 17 wherein said processor compares the energy of one or more observed samples based on said received pilot symbols with the energy of said one or more observed samples during the data period, wherein said comparing is performed for subcarriers in said one or more clusters;

and

sums the comparison results for each subcarrier.