IP Library Granted Patent US 9,596,327
Granted Patent B2
US 9,596,327 · App. 15/148,186 · Granted Mar 14, 2017

Method of detecting packet bandwidth in a wireless OFDM network with multiple overlapped frequency bands

Inventor: Joon Bae Kim (Lexington, MA)
Assignee: APPLIED TRANSFORM, LLC
H04L69/22H04L1/0042H04L1/0056H04L1/0072H04L1/04H04L1/08H04L5/0007H04L5/0037H04L5/0053H04L5/0091H04L27/2602H04L27/2608H04L45/74H04W72/04H04W72/0446H04W72/0453H04W84/12
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Quick Facts
Patent No.
US 9,596,327
App. No.
15/148,186
Granted
Mar 14, 2017
Kind
B2
Abstract

A wireless OFDM transceiver uses a method of detecting subcarrier characteristics, such as phase and amplitude, to determine the bandwidth of a received packet. By detecting different subcarrier characteristics in the long training symbols of a packet at the receiver, the packet is associated with different bandwidths. The different bandwidths are used in a wireless network where devices can communicate using two frequency bands that overlap one another and where one is wider than the other.

Claims (68)

1. A method in a wireless OFDM transceiver, the method comprising:

receiving, by a receiver, a first packet using wireless OFDM communications, wherein the first packet comprises a first plurality of short training symbols followed by a first plurality of long training symbols followed by a first header portion;

detecting, by a demodulator/decoder module connected to and in communication with the receiver, that the first packet is associated with a first channel bandwidth based on at least a first phase of at least one subcarrier in the first plurality of long training symbols;

receiving, by the receiver, a second packet using wireless OFDM communications, wherein the second packet comprises a second plurality of short training symbols followed by a second plurality of long training symbols followed by a second header portion; and

detecting, by the demodulator/decoder, that the second packet is associated with a second channel bandwidth based on at least a second phase of the at least one subcarrier in the second plurality of long training symbols,

wherein the first phase is different than the second phase,

wherein the first channel bandwidth and the second channel bandwidth have one or more overlapping frequency regions, and

wherein the second channel bandwidth is wider than the first channel bandwidth; and

receiving, by the receiver, a first plurality of header information bits in the first header portion using a first mapping of header information bits to subcarriers in the one or more overlapped frequency regions in the first channel bandwidth, wherein the first mapping determines a first order in which the first plurality of header information bits are mapped to subcarriers; and

receiving, by the receiver, a second plurality of header information bits in the second header portion using a second mapping, different than the first mapping, of header information bits to subcarriers in the one or more overlapped frequency regions in the second channel bandwidth wherein the second mapping determines a second order, different than the first order, in which the second plurality of header information bits are mapped to subcarriers.

2. The method of claim 1 , wherein the first header portion indicates a recipient of the first packet.

3. The method of claim 1 , wherein each of the first plurality of long training symbols comprise a first number of subcarriers and each of the second plurality of long training symbols comprise a second number of subcarriers, wherein the first number and second number are different.

4. The method of claim 1 , wherein the second header portion indicates a recipient of the second packet.

5. The method of claim 1 , wherein the wireless OFDM transceiver supports IEEE 802.11 protocols.

6. The method of claim 1 , wherein the difference in the first and second mapping requires the detection that the first packet is associated with the first channel bandwidth to be performed prior to decoding the first header portion.

7. The method of claim 1 , wherein the second channel bandwidth is twice as wide as the first channel bandwidth.

8. The method of claim 1 , wherein a cyclic prefix of at least one of the first plurality of long training symbols is different than the cyclic prefix of at least one of the second plurality of long training symbols.

9. The method of claim 1 , wherein the difference in the first and second mapping requires the detection that the second packet is associated with the second channel bandwidth to be performed prior to decoding the second header portion.

10. A method in a wireless OFDM transceiver, the method comprising:

receiving, by a receiver, a first packet using wireless OFDM communications, wherein the first packet comprises a first plurality of short training symbols followed by a first plurality of long training symbols followed by a first header portion; and

using, by a demodulator/decoder module connected to and in communication with the receiver, at least a first phase of at least one subcarrier in the first plurality of long training symbols to determine that the first packet is associated with a first channel bandwidth of X MHz;

receiving, by the receiver, a second packet using wireless OFDM communications, wherein the second packet comprises a second plurality of short training symbols followed by a second plurality of long training symbols followed by a second header portion; and

using, by the demodulator/decoder module connected to and in communication with the receiver, at least a second phase of the at least one subcarrier in the second plurality of long training symbols to determine that the second packet is associated with a second channel bandwidth of 2X MHz, wherein X is a number greater than 0,

wherein the first phase is different than the second phase,

wherein the first and second channel bandwidth have one or more overlapping frequency regions; and

receiving, by the receiver, a first plurality of header information bits in the first header portion using a first mapping of header information bits to subcarriers in the one or more overlapping frequency regions in the first channel bandwidth, wherein the first mapping determines a first order in which the first plurality of header information bits are mapped to subcarriers; and

receiving, by the receiver, a second plurality of header information bits in the second header portion using a second mapping, different than the first mapping, of header information bits to subcarriers in the one or more overlapping frequency regions in the second channel bandwidth wherein the second mapping determines a second order, different than the first order, in which the second plurality of header information bits are mapped to subcarriers.

11. The method of claim 10 , wherein the first header portion indicates a recipient of the first packet.

12. The method of claim 10 , wherein the second header portion indicates a recipient of the second packet.

13. The method of claim 10 , wherein the wireless OFDM transceiver supports IEEE 802.11 protocols.

14. The method of claim 10 , wherein the difference in the first and second mapping requires the determination that the first packet is associated with the first channel bandwidth to be performed prior to decoding the first header portion.

15. The method of claim 10 , wherein each of the first plurality of long training symbols comprise a first number of subcarriers and each of the second plurality of long training symbols comprise a second number of subcarriers, wherein the first number and second number are different.

16. The method of claim 10 , wherein a cyclic prefix of at least one of the first plurality of long training symbols is different than the cyclic prefix of at least one of the second plurality of long training symbols.

17. The method of claim 10 , wherein the difference in the first and second mapping requires the detection that the second packet is associated with the second channel bandwidth to be performed prior to decoding the second header portion.

18. A method in a wireless OFDM transceiver, the method comprising:

receiving, by a receiver, a first packet using wireless OFDM communications, wherein the first packet comprises a first plurality of short training symbols followed by a first plurality of long training symbols followed by a first header portion;

detecting, by a demodulator/decoder module, connected to and in communication with the receiver, that the first packet is associated with a first channel bandwidth based on at least a first amplitude of at least one subcarrier in the first plurality of long training symbols;

receiving, by the receiver, a second packet using wireless OFDM communications, wherein the second packet comprises a second plurality of short training symbols followed by a second plurality of long training symbols followed by a second header portion;

detecting, by the demodulator/decoder module, that the second packet is associated with a second channel bandwidth based on at least a second amplitude of the at least one subcarrier in the second plurality of long training symbols,

wherein the first amplitude is different than the second amplitude,

wherein the first channel bandwidth and the second channel bandwidth have one or more overlapping frequency regions, and

wherein the second channel bandwidth is wider than the first channel bandwidth, and

receiving, by the receiver, a first plurality of header information bits in the first header portion using a first mapping of header information bits to subcarriers in the one or more overlapping frequency regions in the first channel bandwidth, wherein the first mapping determines a first order in which the first plurality of header information bits are mapped to subcarriers; and

receiving, by the receiver, a second plurality of header information bits in the second header portion using a second mapping, different than the first mapping, of header information bits to subcarriers in the one or more overlapping frequency regions in the second channel bandwidth wherein the second mapping determines a second order, different than the first order, in which the second plurality of header information bits are mapped to subcarriers.

19. The method of claim 18 , wherein each of the first plurality of long training symbols comprise a first number of subcarriers and each of the second plurality of long training symbols comprise a second number of subcarriers, wherein the first number and second number are different.

20. The method of claim 18 , wherein the first header portion indicate a recipient of the first packet.

21. The method of claim 18 , wherein the second header portion indicate a recipient of the second packet.

22. The method of claim 18 , wherein the wireless OFDM transceiver supports IEEE 802.11 protocols.

23. The method of claim 18 , wherein the difference in the first and second mapping requires the detection that the first packet is associated with the first channel bandwidth to be performed prior to decoding the first header portion.

24. The method of claim 18 , wherein the second channel bandwidth is twice as wide as the first channel bandwidth.

25. The method of claim 18 , wherein a cyclic prefix of at least one of the first plurality of long training symbols is different than the cyclic prefix of at least one of the second plurality of long training symbols.

26. The method of claim 18 , wherein the difference in the first and second mapping requires the detection that the second packet is associated with the second channel bandwidth to be performed prior to decoding the second header portion.

27. A method in a wireless OFDM transceiver, the method comprising:

receiving, by a receiver, a first packet using wireless OFDM communications, wherein the first packet comprises a first plurality of short training symbols followed by a first plurality of long training symbols followed by a first header portion; and

using, by a demodulator/decoder module connected to and in communication with the receiver, at least a first amplitude of at least one subcarrier in the first plurality of long training symbols to determine that the first packet is associated with a first channel bandwidth of X MHz;

receiving, by the receiver, a second packet using wireless OFDM communications, wherein the second packet comprises a second plurality of short training symbols followed by a second plurality of long training symbols followed by a second header portion; and

using, by the demodulator/decoder module connected to and in communication with the receiver, at least a second amplitude of the at least one subcarrier in the second plurality of long training symbols to determine that the second packet is associated with a second channel bandwidth of 2X, wherein X is a number greater than zero,

wherein the first amplitude is different than the second amplitude,

wherein the first and second channel bandwidth have one or more overlapping frequency regions; and

receiving, by the receiver, a first plurality of header information bits in the first header portion using a first mapping of header information bits to subcarriers in the one or more overlapping frequency regions in the first channel bandwidth, wherein the first mapping determines a first order in which the first plurality of header information bits are mapped to subcarriers; and

receiving, by the receiver, s a second plurality of header information bits in the second header portion using a second mapping, different than the first mapping, of header information bits to subcarriers in the one or more overlapping frequency regions in the second channel bandwidth wherein the second mapping determines a second order, different than the first order, in which the second plurality of header information bits are mapped to subcarriers.

28. The method of claim 27 , wherein the first header portion indicates a recipient of the first packet.

29. The method of claim 27 , wherein the second header portion indicates a recipient of the second packet.

30. The method of claim 27 , wherein the wireless OFDM transceiver supports IEEE 802.11 protocols.

31. The method of claim 27 , wherein the difference in the first and second mapping requires the detection that the first packet is associated with the first channel bandwidth to be performed prior to decoding the first header portion.

32. The method of claim 27 , wherein each of the first plurality of long training symbols comprise a first number of subcarriers and each of the second plurality of long training symbols comprise a second number of subcarriers, wherein the first number and second number are different.

33. The method of claim 27 , wherein a cyclic prefix of at least one of the first plurality of long training symbols is different than the cyclic prefix of at least one of the second plurality of long training symbols.

34. The method of claim 27 , wherein the difference in the first and second mapping requires the detection that the second packet is associated with the second channel bandwidth to be performed prior to decoding the second header portion.

Continuity (5)
Continuation 12783903 · May 20, 2010
Continuation 12743876
Provisional Application 61091621 · Aug 25, 2008
Provisional Application 61196068 · Oct 14, 2008
Related Publication 20160255178A1 · Sep 1, 2016