Frequency hop sequences for multi-band communication systems

• US 20040161018A1
• Filed: 02/18/2003
• Published: 08/19/2004
• Est. Priority Date: 02/18/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Maric, Svetislav
• Granted Patent: US 7,068,703 B2
• Time in Patent Office: Days
• US Class Current: 375/136
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0041 Frequency-non-contiguous
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority

Abstract

Techniques to generate FH sequences having excellent correlation properties and to use these FH sequences in multi-band communication systems (e.g., OFDM systems). In one aspect, FH sequences may be generated based on an algebraic expression y(k)=log_αb/k (mod p), where k is an index, p is an odd prime number, α is a primitive root of p, b is an integer, and (mod p) denotes modulo-p operation. Different FH sequences may be generated with different values for b, α, and/or p. In another aspect, data may be transmitted using FH sequences generated based on the expression y(k)=log_αb/k (mod p). In a first scheme, data may be transmitted on “traffic” channels, each of which may be associated with a respective FH sequence that determines the specific subband to use in each slot. In a second scheme, each data transmission is sent on subbands determined based on all or a portion of an FH sequence.

Claims

1. A method of obtaining a frequency hop (FH) sequence, comprising:

obtaining a first sequence of elements for an expression 1/k, where k is an index for the elements in the first sequence; and

obtaining a second sequence of elements for an expression log_α

1/k based on the first sequence, where p is a prime number and α

is a primitive root of p, wherein the expressions 1/k and log_α

1/k are evaluated with modulo-p operation, and wherein the FH sequence is derived based on the second sequence.

2. The method of claim 1, further comprising:

obtaining a third sequence of elements for an expression α

^k, wherein the second sequence is further obtained based on the third sequence.

3. The method of claim 1, wherein the FH sequence is equal to the second sequence.

4. The method of claim 1, wherein the FH sequence is a vertically shifted version of the second sequence.

5. The method of claim 1, further comprising:

selecting the prime number p based on a desired length for the second sequence.

6. The method of claim 1, wherein the FH sequence is used to determine a particular frequency band from among a plurality of frequency bands to use for data transmission in each of a plurality of time intervals.

7. A method of processing data for transmission in a multi-band communication system, comprising:

receiving data for transmission on a plurality of frequency bands;

determining a particular one of the plurality of frequency bands to use in each of a plurality of time intervals based on a frequency hop (FH) sequence, wherein the FH sequence is generated based on an algebraic expression y(k)=log_α

1/k (mod p), where p is a prime number, α

is a primitive root of p, k is an index for elements of the FH sequence, and (mod p) denotes modulo-p operation; and

processing the data for transmission on frequency bands determined by the FH sequence.

8. The method of claim 7, wherein the data is processed for transmission on frequency bands corresponding to a portion of the FH sequence.

9. The method of claim 7, wherein the multi-band communication system implements orthogonal frequency division multiplexing (OFDM), and wherein the plurality of frequency bands correspond to subbands provided by OFDM.

10. The method of claim 9, wherein each time interval has a duration of one OFDM symbol period.

11. An apparatus in a multi-band communication system, comprising:

means for receiving data for transmission on a plurality of frequency bands;

means for determining a particular one of the plurality of frequency bands to use in each of a plurality of time intervals based on a frequency hop (FH) sequence, wherein the FH sequence is generated based on an algebraic expression y(k)=log_α

1/k (mod p), where p is a prime number, α

is a primitive root of p, k is an index for elements of the FH sequence, and (mod p) denotes modulo-p operation; and

means for processing the data for transmission on frequency bands determined by the FH sequence.

12. The apparatus of claim 11, wherein the data transmission is for a downlink in the multi-band communication system.

13. The apparatus of claim 11, wherein the data transmission is for an uplink in the multi-band communication system.

14. A transmitter unit in a multi-band communication system, comprising:

a modulator operative to modulate data for transmission on a plurality of frequency bands;

a switch operative to determine a particular one of the plurality of frequency bands to use in each of a plurality of time intervals based on a frequency hop (FH) sequence, wherein the FH sequence is generated based on an algebraic expression y(k)=log_α

1/k (mod p), where p is a prime number, α

is a primitive root of p, k is an index for elements of the FH sequence, and (mod p) denotes modulo-p operation; and

a signal processor operative to process the modulated data for transmission on frequency bands determined by the FH sequence.

15. The transmitter unit of claim 14, wherein the multi-band communication system implements orthogonal frequency division multiplexing (OFDM), wherein the plurality of frequency bands correspond to subbands provided by OFDM, and wherein the signal processor performs inverse Fourier transform on the modulated data.

16. A method of processing data for transmission in a multi-band communication system, comprising:

receiving data for transmission on a first traffic channel;

determining a particular one of a plurality of frequency bands to use for the first traffic channel in each of a plurality of time intervals based on a first frequency hop (FH) sequence, wherein the first FH sequence is assigned to the first traffic channel and generated based on an algebraic expression y(k)=log_α

1/k (mod p), where p is a prime number, α

is a primitive root of p, k is an index for elements of the first FH sequence, and (mod p) denotes modulo-p operation; and

processing the data for the first traffic channel for transmission on frequency bands determined by the first FH sequence.

17. The method of claim 16, further comprising:

receiving data for transmission on a second traffic channel;

determining a particular one of the plurality of frequency bands to use for the second traffic channel in each time interval based on a second FH sequence, wherein the second FH sequence is assigned to the second traffic channel and generated based on the algebraic expression y(k)=log_α

1/k (mod p); and

processing the data for the second traffic channel for transmission on frequency bands determined by the second FH sequence.

18. The method of claim 17, wherein the second FH sequence is a vertically shifted version of the first FH sequence.

19. The method of claim 17, wherein the first and second FH sequences are generated based on different primitive roots of the same prime number.

20. The method of claim 17, wherein the first and second FH sequences are generated based on different prime numbers.

21. The method of claim 16, wherein the multi-band communication system implements orthogonal frequency division multiplexing (OFDM), and wherein the plurality of frequency bands correspond to subbands provided by OFDM.

22. A method of recovering a data transmission in a multi-band communication system, comprising:

obtaining received symbols for a plurality of frequency bands;

determining a particular one of the plurality of frequency bands used for the data transmission in each of a plurality of time intervals based on a frequency hop (FH) sequence, wherein the FH sequence is assigned to the data transmission and generated based on an algebraic expression y(k)=log_α

1/k (mod p), where p is a prime number, α

is a primitive root of p, k is an index for elements of the FH sequence, and (mod p) denotes modulo-p operation; and

processing received symbols for frequency bands determined by the FH sequence to recover the data transmission.

23. An apparatus in a multi-band communication system, comprising:

means for obtaining received symbols for a plurality of frequency bands;

means for determining a particular one of the plurality of frequency bands used for the data transmission in each of a plurality of time intervals based on a frequency hop (FH) sequence, wherein the FH sequence is assigned to the data transmission and generated based on an algebraic expression y(k)=log_α

1/k (mod p), where p is a prime number, α

is a primitive root of p, k is an index for elements of the FH sequence, and (mod p) denotes modulo-p operation; and

means for processing received symbols for frequency bands determined by the FH sequence to recover the data transmission.