WIRELESS LOCAL AREA NETWORK USING TV WHITE SPACE SPECTRUM AND LONG TERM EVOLUTION SYSTEM ARCHITECTURE

• US 20100195580A1
• Filed: 01/30/2009
• Published: 08/05/2010
• Est. Priority Date: 01/30/2009
• Status: Active Grant

• Current Assignee: Wi-LAN Inc.
• Original Assignee: Wi-LAN Inc.
• Inventors: Wu, Shiquan, Samarasooriya, Vajira
• Granted Patent: US 8,335,204 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• 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 Long Term Evolution (LTE) downlink frames in which at least a predetermined subset of pilot symbol positions used in the LTE downlink frames to transmit pilot symbols for channel estimation maybe filled with control data symbols to increase a data capacity of each of the LTE downlink frames; and

a data sink that receives the modified LTE frames 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 further comprises a TV white space transceiver for transmitting the modified LTE frames using unlicensed 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 available TV white space spectrum for use by the local area network.

5. The wireless local area network as claimed in claim 2 wherein the data sink further comprises a TV white space receiver for receiving the modified LTE downlink frames 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 received LTE downlink frames and extracts the data from the predetermined subset of pilot positions.

7. The wireless local area network as claimed in claim 1 a wherein the data sink further comprises a channel estimator for computing channel estimations using pilot symbols in the received LTE downlink frames, 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 modified Long Term Evolution (LTE) downlink frames in which a predetermined subset of the pilot symbols used for channel estimation in the LTE downlink frames are replaced with control data symbols to increase the spectrum efficiency.

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 frames.

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 use by the local area network gateway.

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 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 a TV white space 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 in each of the modified LTE downlink frames.

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 used in LTE downlink frames to transmit pilot symbols for channel estimation are filled with 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 a 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 wherein before beginning to transmit the modified LTE downlink frames, the method further comprises 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 wherein before transmitting a modified LTE downlink frame, the method further comprises 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.