METHOD AND APPARATUS FOR DYNAMIC BANDWIDTH PROVISIONING IN FREQUENCY DIVISION DUPLEX SYSTEMS

• US 20120063373A1
• Filed: 09/14/2011
• Published: 03/15/2012
• Est. Priority Date: 09/15/2010
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Demir, Alpaslan, Haque, Tanbir, Chincholi, Amith V.
• Granted Patent: US 9,413,500 B2
• Time in Patent Office: Days
• US Class Current: 370/281
• CPC Class Codes: H04B 7/00 Radio transmission systems, i.e. using radiation field H04B10/00, H04B15/00 take precedence
• CPC Class Codes: H04J 1/00 Frequency-division multiplex systems H04J14/00 takes precedence
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0071 Allocation based on fairness other than the proportional kind
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A method and apparatus are described that provides flexible spectrum usage by using a paired frequency division duplex (FDD) spectrum to enable dynamic access in television white space (TVWS), sub-leased spectrum or unlicensed spectrum, (e.g., industrial, scientific and medical (ISM) bands), in a femto cell environment or the like. Elastic FDD (E-FDD) enables femto cell operation in TVWS, sub-leased spectrum and/or unlicensed spectrum, either simultaneously with licensed spectrum or as an alternate channel to licensed spectrum. E-FDD enables dynamic asymmetric bandwidth allocation for uplink (UL) and downlink (DL) in FDD, and enables variable duplex spacing, (i.e., using FDD with minimum duplex spacing between DL and UL spectrum, or, using hybrid-FDD, (FDD in a time duplexed fashion), when a spectrum gap between the UL and DL spectrum is below a certain minimum threshold. Additionally, the signaling enhancements to implement E-FDD are also provided.

Claims

1. A method of implementing frequency division duplex (FDD), the method comprising:

assessing spectrum usage for uplink (UL) and downlink (DL) based on spectrum usage information;

determining availability of spectrum; and

dynamically allocating UL spectrum and the DL spectrum from the spectrum in view of spectrum usage assessment and spectrum availability.

2. The method of claim 1, wherein the spectrum is at least one of licensed, sub-leased, whitespace or unlicensed spectrum.

3. The method of claim 1, wherein the spectrum usage information is at least one of traffic patterns, bandwidth requirements or quality of service requirements.

4. The method of claim 1, wherein the spectrum availability information is based on at least one of sensing, or centralized database access.

5. The method of claim 1, wherein spectrum allocation is asymmetric.

6. The method of claim 1, wherein spacing between the UL spectrum and the DL spectrum is variable.

7. The method of claim 1, wherein the UL and the DL communicate simultaneously on a condition that the spacing between the UL spectrum and the DL spectrum is greater than a threshold.

8. The method of claim 1, wherein a hybrid FDD scheme is used to prevent leakage of a transmit chain signal into a receive chain on a condition that spacing between the UL spectrum and the DL spectrum is less than a threshold.

9. The method of claim 1, wherein an adaptive self-interference cancellation scheme is used in the radio frequency (RF) front-end at transmitter and receiver to prevent leakage of the transmit chain signal into the receive chain on a condition that spacing between the UL spectrum and the DL spectrum is less than a threshold to enable full duplex FDD.

10. The method of claim 1, wherein dynamic allocation of available whitespace spectrum occurs in the presence of a primary user.

11. The method of claim 1, wherein dynamic allocation of available unlicensed spectrum occurs in the presence of secondary users.

12. The method of claim 10, further comprising:

detecting the presence of the primary user on the available whitespace spectrum on a condition that the primary user is now using previously available whitespace spectrum;

dynamically allocating the UL spectrum and the DL spectrum around the primary user'"'"'s transmission in the previously available unlicensed spectrum; and

maintaining communication between a base station and at least one wireless transmit/receive unit regardless of the presence of the primary user by avoiding interference with the primary user transmission.

13. The method of claim 1, wherein self-interference between a transmit chain and a receive chain due to minimal or no duplex spacing is mitigated by using one of adaptive cancellation or hybrid FDD (H-FDD).

14. The method of claim 1, further comprising:

moving one of the UL spectrum and the DL spectrum to at least one of a sub-leased, whitespace or unlicensed spectrum due to operational conditions, wherein the UL spectrum and the DL spectrum were using licensed spectrum.

15. The method of claim 1, further comprising:

dynamically swapping between licensed spectrum and at least one of sub-leased, whitespace or unlicensed spectrum.

16. The method claim 1, further comprising:

determining at least one of sub-leased, whitespace or unlicensed channel availability;

selecting at least one of sub-leased, whitespace or unlicensed channel based on bandwidth requirement for the UL and the DL;

allocating a selected sub-leased, whitespace or unlicensed channel; and

communicating on an allocated sub-leased, whitespace or unlicensed channel and a licensed channel.

17. The method claim 1, further comprising:

allocating a portion of one of the UL spectrum or the DL spectrum to the remaining one of the DL spectrum or the UL spectrum, respectively.

18. The method of claim 1, further comprising:

aggregating licensed spectrum with at least one of sub-leased, whitespace or unlicensed spectrum, wherein the UL spectrum and the DL spectrum both include aggregated licensed spectrum and unlicensed spectrum.

19. A wireless communications system, comprising:

a processor configured to assess spectrum usage for uplink (UL) and downlink (DL) based on spectrum usage information;

the processor further configured to determine availability of spectrum, wherein the spectrum is at least one of licensed, sub-leased, whitespace or unlicensed spectrum; and

the processor further configured to dynamically allocate UL spectrum and the DL spectrum from the spectrum in view of spectrum usage assessment and spectrum availability, wherein spacing between the UL spectrum and the DL spectrum is variable.

20. The wireless communications system of claim 19, further comprising:

the processor further configured to aggregate licensed spectrum with at least one of sub-leased, whitespace or unlicensed spectrum, wherein the UL spectrum and the DL spectrum both include aggregated licensed spectrum and at least one of sub-leased, whitespace or unlicensed spectrum.