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

• US 8,848,644 B2
• Filed: 08/29/2012
• Issued: 09/30/2014
• Est. Priority Date: 01/30/2009
• Status: Expired due to Fees

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Inventors: Samarasooriya, Vajira, Wu, Shiquan
• Primary Examiner(s): HOANG, THAI D
• Application Number:
  US13/597,607
• Publication Number:
  US 20120320865A1
• Time in Patent Office: 762 Days
• Field of Search: 370/208, 370343-345, 370329-330, 375/260
• 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 uses a LTE radio frame and TV white space spectrum for data communications in a wireless local area network. In the LTE downlink frame, a predefined subset of the pilot (reference) symbol positions are used to carry information to data sinks in the WLAN.

Claims

1. A wireless local area network, comprising:

a local area network gateway configured to communicate modified OFDM frames over a piece of vacant white space, the modified OFDM frames comprising a predetermined subset of pilot symbol positions normally used in OFDM frames to transmit pilot symbols for channel estimation that are made available for carrying control symbols to increase a data capacity of each of the modified OFDM frames; and

a receiver configured to receive the modified OFDM frames and extract the control 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 OFDM frames over 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 configured to receive from the spectrum sensing unit information about the sensed TV band over-the-air signals and select the piece of vacant white space for transmitting the modified OFDM frames.

5. The wireless local area network as claimed in claim 2, wherein the receiver comprises a TV white space receiver for receiving the modified OFDM frames transmitted by the local area network gateway.

6. The wireless local area network as claimed in claim 5, wherein the receiver further comprises a frame processor configured to demodulate the modified OFDM frames and extract the control symbols from the predetermined subset of pilot positions.

7. The wireless local area network as claimed in claim 1, wherein the receiver comprises a channel estimator for computing channel estimations using pilot symbols in the modified OFDM frames, and interpolation algorithms for interpolating 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 OFDM frames.

8. A local area network gateway comprising a transceiver configured to communicate modified OFDM frames over a piece of vacant white space, the modified OFDM frames comprising a predetermined subset of pilot symbol positions normally used to transmit pilot symbols for channel estimation in OFDM frames that are made available for carrying control symbols to increase a data capacity of the modified OFDM frames.

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 OFDM frames.

10. The local area network gateway as claimed in claim 8, 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 configured to receive information about the sensed TV band over-the-air signals from the spectrum sensing unit and select the piece of vacant white space for transmitting the modified OFDM frames.

12. A receiver for use in a local area network, comprising an OFDM frame processor configured to process modified OFDM frames transmitted by a local area network gateway and extract control symbols from a predetermined subset of pilot symbol positions normally used in OFDM frames to transmit pilot symbols for channel estimation, the predetermined subset of pilot symbol positions made available for carrying the control symbols in the modified OFDM frames.

13. The receiver as claimed in claim 12, further comprising an antenna for receiving the modified OFDM frames from a piece of vacant white space.

14. The receiver as claimed in claim 12, further comprising a channel estimator configured to compute channel estimations using pilot symbols transmitted on pilot positions in the modified OFDM frames not included in the predetermined subset of pilot symbol positions.

15. The receiver as claimed in claim 14, wherein the channel estimator comprises channel estimation interpolation algorithms configured to 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 OFDM frames.

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

transmitting modified OFDM frames over a piece of vacant white space, the modified OFDM frames comprising a predetermined subset of pilot symbol positions normally used in OFDM frames to transmit pilot symbols for channel estimation that are made available for carrying control symbols to increase a data capacity of the modified OFDM frames; and

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

17. The method as claimed in claim 16, wherein the piece of vacant white space is 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 OFDM frames.

19. The method as claimed in claim 16, further comprising inserting at least one source data packet into the modified OFDM frames.

20. The method as claimed in claim 19, further comprising, after extracting the control symbols from the predetermined subset of the pilot symbol positions, inspecting the modified OFDM frames for a source data packet.