Methods and apparatus for adjusting bandwidth allocation in a wireless communications system

• US 20060083211A1
• Filed: 10/11/2005
• Published: 04/20/2006
• Est. Priority Date: 10/14/2004
• Status: Active Grant

• Current Assignee: Inteva Products France SAS
• Original Assignee: Qualcomm, Inc.
• Inventors: Laroia, Rajiv, Li, Junyi, Parizhsky, Vladimir
• Granted Patent: US 7,567,502 B2
• Time in Patent Office: Days
• US Class Current: 370/343
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/26025 Numerology, i.e. varying one or more of symbol duration, subcarrier spacing, Fourier transform size, sampling rate or down-clocking allocating sub-channels of the transmission path H04L5/003
• CPC Class Codes: H04L 5/0042 intra-user or intra-terminal allocation

Abstract

More efficient utilization of available bandwidth is implemented in an OFDM wireless communication system. The partitions of bandwidth may be of different sizes and may be different from the original system design parameters. Basic system structure such as the number of tones used and the number of OFDM symbol times in a slot is maintained throughout the system. Bandwidth is varied by adjusting the inter-tone spacing or bandwidth associated with a single tone. As the inter-tone spacing is increased, the OFDM symbol transmission time is decreased following an inverse proportional relationship. A first base station transmitter transmits signals on a first number of tones distributed uniformly in a first frequency band, and a second base station transmitter transmits signals on a second number of tones distributed uniformly in a second frequency band which is wider than the first frequency band, the second number of tones being the same as the first number of tones. The first and second base stations support handoffs of mobile nodes between to each other.

Claims

1. A communications method, comprising:

operating a first transmitter to transmit signals on a first number of tones distributed uniformly in a first frequency band; and

operating a second transmitter to transmit signals on a second number of tones distributed uniformly in a second frequency band which is wider than said first frequency band, said second number of tones being the same as said first number of tones.

2. The method of claim 1, wherein said first number of tones is at least 10.

3. The method of claim 2, wherein said first and second transmitters are both OFDM transmitters.

4. The method of claim 1, further comprising:

using a first set of stored control channel structure information to control the transmission by said first transmitter of at least some control signals according to a predetermined recurring transmission pattern; and

using a second set of stored control channel structure information to control the transmission by said second transmitter of at least some control signals according to said predetermined recurring transmission pattern.

5. The method of claim 4, wherein the period of the recurring transmission pattern used by the first and second transmitters being different by an amount proportional to a difference in symbol transmission durations, where the difference in symbol transmission durations is the difference in the duration of symbol transmission times at said first transmitter to the duration of symbol transmission times at said second transmitter.

6. The method of claim 1, further comprising:

generating symbol transmission timing control signals used to control the duration of symbols transmitted by said first transmitter, the symbol duration including a cyclic prefix portion and a symbol body portion; and

generating symbol transmission timing control signals used to control the duration of symbols transmitted by said second transmitter, the duration of symbols transmitted by said second transmitter being shorter than the duration of symbols transmitted by said first transmitter, the ratio of i) the duration of the body portion of symbols transmitted by said first transmitter to ii) the duration of the body portion of symbols transmitted by said second transmitter being the same as the ratio of iii) the bandwidth of the second frequency band to iv) the bandwidth of the first frequency band.

7. The method of claim 6, wherein the ratio of i) the duration of the cyclic prefix portion of symbols transmitted by said first transmitter to ii) the duration of the cyclic prefix portion of symbols transmitted by said second transmitter is also the same as the ratio of iii) the bandwidth of the second frequency band to iv) the bandwidth of the first frequency band.

8. The method of claim 4, further comprising:

generating symbol transmission timing control signals used to control the duration of symbols transmitted by said first transmitter; and

generating symbol transmission timing control signals used to control the duration of symbols transmitted by said second transmitter, the duration of symbols transmitted by said second transmitter being shorter than the duration of symbols transmitted by said first transmitter.

9. The method of claim 8, wherein the ratio of i) the duration of the symbols transmitted by the first transmitter to ii) the duration of the symbols transmitted by the second transmitter being equal to the ratio of iii) the frequency spacing between two adjacent tones transmitted by said second transmitter to iv) the frequency spacing between two adjacent tones transmitted by said first transmitter.

10. The method of claim 9, wherein said ratio is less than 1.3 to 1.

11. The method of claim 9, wherein said first and second transmitters are located in different base stations.

12. The method of claim 11, wherein said first and second transmitters are OFDM transmitters;

wherein one of said first and second transmitters operates in a portion of a 2.5 GHz frequency band; and

wherein the other one of said first and second transmitters operates in a portion of a 450 MHz frequency band.

13. The method of claim 11, further comprising:

operating the first base station to complete a mobile node handoff operation to said second base station.

14. The method of claim 13, further comprising:

operating said second base station to transmit packets to said mobile node corresponding to a communications session that was ongoing at said first base station prior to said handoff.

15. The method of claim 11, further comprising:

using the same recurring control signaling pattern for uplink control signaling in each of different base station.

16. A communications system, comprising:

a first transmitter to transmit signals on a first number of tones distributed uniformly in a first frequency band; and

a second transmitter to transmit signals on a second number of tones distributed uniformly in a second frequency band which is wider than said first frequency band, said second number of tones being the same as said first number of tones.

17. The system of claim 16, wherein said first number of tones is at least 10.

18. The system of claim 17, wherein said first and second transmitters are both OFDM transmitters.

19. The system of claim 18, wherein said first and second transmitters are located in different base stations.

20. The system of claim 18, wherein said first and second transmitters are located in a base station.

21. The system of claim 20, wherein said first and second transmitters are both located in different sectors of said base station.

22. The system of claim 20, wherein said first and second transmitters are located in the same sector of a base station.

23. The system of claim 16, further comprising:

a first memory including a first set of stored control channel structure information for controlling the transmission by said first transmitter of at least some control signals according to a predetermined recurring transmission pattern; and

a second memory including a second set of stored control channel structure information to control the transmission by said second transmitter of at least some control signals according to said predetermined recurring transmission pattern.

24. The system of claim 23, wherein the period of the recurring transmission pattern used by the first and second transmitters is different by an amount proportional to a difference in symbol transmission durations, where the difference in symbol transmission durations is the difference in the duration of symbol transmission times at said first transmitter to the duration of symbol transmission times at said second transmitter.

25. The system of claim 16, further comprising:

a first timing control module for generating symbol transmission timing control signals used to control the duration of symbols transmitted by said first transmitter, the symbol duration including a cyclic prefix portion and a symbol body portion; and

a second timing control module for generating symbol transmission timing control signals used to control the duration of symbols transmitted by said second transmitter, the duration of symbols transmitted by said second transmitter being shorter than the duration of symbols transmitted by said first transmitter, the ratio of i) the duration of the body portion of symbols transmitted by said first transmitter to ii) the duration of the body portion of symbols transmitted by said second transmitter being the same as the ratio of iii) the bandwidth of the second frequency band to iv) the bandwidth of the first frequency band.

26. The system of claim 25, wherein the ratio of i) the duration of the cyclic prefix portion of symbols transmitted by said first transmitter to ii) the duration of the cyclic prefix portion of symbols transmitted by said second transmitter is also the same as the ratio of iii) the bandwidth of the second frequency band to iv) the bandwidth of the first frequency band.

27. The system of claim 23, further comprising:

a first timing control module for generating symbol transmission timing control signals used to control the duration of symbols transmitted by said first transmitter; and

a second timing control module for generating symbol transmission timing control signals used to control the duration of symbols transmitted by said second transmitter, the duration of symbols transmitted by said second transmitter being shorter than the duration of symbols transmitted by said first transmitter.

28. The system of claim 27, wherein the ratio of i) the duration of the symbols transmitted by the first transmitter to ii) the duration of the symbols transmitted by the second transmitter being equal to the ratio of iii) the frequency spacing between two adjacent tones transmitted by said second transmitter to iv) the frequency spacing between two adjacent tones transmitted by said first transmitter.

29. The system of claim 28, wherein said ratio is less than 1.3 to 1.

30. The system of claim 28, wherein said first and second transmitters are located in different base stations.

31. The system of claim 30, wherein said first and second transmitters are OFDM transmitters;

wherein one of said first and second transmitters operates in a portion of a 2.5 GHz frequency band; and

wherein the other one of said first and second transmitters operates in a portion of a 450 MHzfrequency band.

32. The system of claim 30, further comprising:

a handoff control module in said first base station for controlling the first base station to complete a mobile node handoff operation to said second base station.

33. The system of claim 32, further comprising:

a packet transmission control module for controlling said second base station to transmit packets to said mobile node corresponding to a communications session that was ongoing at said first base station prior to said handoff.

34. The system of claim 30, further comprising:

stored information in each of said first and second base stations indicating a recurring control signaling pattern used by both said first and second base stations for uplink control signaling.