Wireless local area network using TV white space spectrum and long term evolution system architecture

• US 8,335,204 B2
• Filed: 01/30/2009
• Issued: 12/18/2012
• Est. Priority Date: 01/30/2009
• Status: Expired due to Fees

• Current Assignee: Wi-LAN Inc.
• Original Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Inventors: Samarasooriya, Vajira, Wu, Shiquan
• Primary Examiner(s): HOANG, THAI D
• Application Number:
  US12/363,319
• Publication Number:
  US 20100195580A1
• Time in Patent Office: 1,418 Days
• Field of Search: 370329-334, 370335-338, 375/131
• US Class Current: 370/347
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

A wireless local area network (WLAN) gateway may use a modified LTE radio frame and TV white space spectrum for data communications in a wireless local area network. In the modified LTE downlink frame a predefined subset of the pilot (reference) symbol subcarriers are used to carry information to data sinks in the WLAN.

Claims

1. A wireless local area network, comprising:

a local area network gateway that transmits a modified Long Term Evolution (LTE) downlink frame in which a predetermined subset of pilot symbol positions used in LTE downlink frames to transmit pilot symbols for channel estimation are used to carry control data symbols to increase a data capacity of each of the LTE downlink frames; and

a data sink that receives the modified LTE downlink frame and extracts the control data symbols from the predetermined subset of pilot symbol positions.

2. The wireless local area network as claimed in claim 1 wherein the local area network gateway comprises a TV white space transceiver for transmitting the modified LTE downlink frame over available TV white space spectrum.

3. The wireless local area network as claimed in claim 2 wherein the local area network gateway further comprises a spectrum sensing unit equipped with an antenna for sensing TV band over-the-air signals.

4. The wireless local area network as claimed in claim 3 wherein the local area network gateway further comprises a spectrum manager that receives from the spectrum sensing unit information about the sensed TV band over-the-air signals and selects the available TV white space spectrum for transmitting the modified LTE downlink frame.

5. The wireless local area network as claimed in claim 2 wherein the data sink comprises a TV white space receiver for receiving the modified LTE downlink frame transmitted by the local area network gateway.

6. The wireless local area network as claimed in claim 1 wherein the data sink further comprises a frame processor that demodulates the modified LTE downlink frame and extracts the control data symbols from the predetermined subset of pilot positions.

7. The wireless local area network as claimed in claim 1 wherein the data sink comprises a channel estimator for computing channel estimations using pilot symbols in the modified LTE downlink frame, and interpolation algorithms that interpolate the computed channel estimations in the frequency domain and the time domain to provide a channel estimate at each received symbol position in the modified LTE downlink frame.

8. A local area network gateway comprising a transceiver that transmits a modified Long Term Evolution (LTE) downlink frame in which a predetermined subset of the pilot symbols used for channel estimation in the LTE downlink frames are replaced with control data symbols that carry control information to a data sink in the local area network.

9. The local area network gateway as claimed in claim 8 wherein the transceiver is a TV white space transceiver that uses TV white space spectrum for transmitting the modified LTE downlink frame.

10. The local area network gateway as claimed in claim 9 further comprising a spectrum sensing unit equipped with an antenna for sensing TV band over-the-air signals.

11. The local area network gateway as claimed in claim 10 further comprising a spectrum manager that receives information about the sensed TV band over-the-air signals from the spectrum sensing unit and selects available TV white space spectrum for transmitting the modified LTE downlink frame.

12. A data sink in a local area network, comprising a Long Term Evolution (LTE) frame processor that processes modified LTE downlink frames transmitted by a local area network gateway and extracts control data symbols from a predetermined subset of pilot symbol positions used to carry the control data in the modified LTE downlink frame.

13. The data sink as claimed in claim 12 further comprising an antenna connected to a TV white space receiver that receives the modified LTE downlink frames.

14. The data sink as claimed in claim 13 further comprising a channel estimator that computes channel estimations using pilot symbols transmitted on pilot positions in a modified downlink frame not included in the predetermined subset.

15. The data sink as claimed in claim 14 wherein the channel estimator further comprises channel estimation interpolation algorithms that interpolate the computed channel estimations in the frequency domain and the time domain to provide a channel estimate at each received symbol position in the modified LTE downlink frame.

16. A method of data communications in a wireless local area network, comprising:

transmitting within the wireless local area network modified Long Term Evolution (LTE) downlink frames in which a predetermined subset of the pilot symbol positions otherwise used in LTE downlink frames to transmit pilot symbols for channel estimation are used to carry control data symbols to increase a data capacity of each of the LTE downlink frames; and

on receipt at a data sink in the wireless local area network of one of the modified LTE downlink frames, demodulating the modified LTE downlink frame and extracting the control data symbols from the predetermined subset of the pilot symbol positions.

17. The method as claimed in claim 16 further comprising transmitting the modified LTE downlink frames using available TV whitespace spectrum.

18. The method as claimed in claim 17 further comprising sensing TV band over-the-air signals and selecting unused TV white space spectrum for transmitting the modified LTE downlink frames.

19. The method as claimed in claim 18 further comprising inserting at least one source data packet into the modified LTE downlink frame.

20. The method as claimed in claim 19 wherein after extracting the control data symbols from the predetermined subset of the pilot symbol positions, the data sink inspects the modified LTE downlink frame for a source data packet.