METHOD OF DETECTING PACKET BANDWIDTH IN A WIRELESS OFDM NETWORK WITH MULTIPLE OVERLAPPED FREQUENCY BANDS

• US 20160255178A1
• Filed: 05/06/2016
• Published: 09/01/2016
• Est. Priority Date: 08/25/2008
• Status: Active Grant

• Current Assignee: Applied Transform LLC
• Original Assignee: Applied Transform LLC
• Inventors: KIM, Joon Bae
• Granted Patent: US 9,596,327 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0056 Systems characterized by the type of code used H04L1/08 takes precedence
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/04 using frequency diversity
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/26025 Numerology, i.e. varying one or more of symbol duration, subcarrier spacing, Fourier transform size, sampling rate or down-clocking allocating sub-channels of the transmission path H04L5/003
• CPC Class Codes: H04L 45/74 Address processing for routing
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• 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 84/12 WLAN [Wireless Local Area Networks]

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

1-330. -330. (canceled)

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

receiving 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 that the first packet is associated with a first channel bandwidth based on at least one of a first phase and a first amplitude of at least one subcarrier in the first plurality of long training symbols;

receiving 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 that the second packet is associated with a second channel bandwidth based on at least one of a second phase and a second amplitude of the at least one subcarrier in the second plurality of long training symbols,

wherein at least one of;

the first phase is different from the second phase, and the first amplitude is different from 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.

332. The method of claim 331, wherein subcarrier indices for receiving a plurality of header information bits in the one or more overlapped frequency regions do not match in the first and second channel bandwidths, wherein the subcarrier indices determine an order in which the plurality of header information bits are mapped to subcarriers.

333. The method of claim 331, 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.

334. The method of claim 331, wherein at least one the first header portion and the second header portion indicates a recipient of the packet.

335. The method of claim 331, wherein the wireless OFDM transceiver supports IEEE 802.11 protocols.

336. The method of claim 331, wherein the detection that the packet is associated with the first channel bandwidth or the second channel bandwidth is performed prior to decoding at least one of the first header portion and the second header portion.

337. The method of claim 331, wherein the second channel bandwidth is twice as wide as the first channel bandwidth.

338. The method of claim 331, 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.

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

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

detecting that the packet is associated with one of a first channel bandwidth and a second channel bandwidth,

wherein the detection that the packet is associated with the first channel bandwidth is based on at least one of a first phase and a first amplitude of at least one subcarrier in the plurality of long training symbols,

wherein the detection that the packet is associated with the second channel bandwidth is based on at least on one of a second phase and a second amplitude of the at least one subcarrier in the plurality of long training symbols,

wherein at least one of;

the first phase is different from the second phase, and the first amplitude is different from 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.

340. The method of claim 339, wherein subcarrier indices for receiving a plurality of header information bits in the one or more overlapped frequency regions do not match in the first and second channel bandwidths, wherein the subcarrier indices determine an order in which the plurality of header information bits are mapped to subcarriers.

341. The method of claim 339, wherein the header portion indicates a recipient of the packet.

342. The method of claim 339, wherein the wireless OFDM transceiver supports IEEE 802.11 protocols.

343. The method of claim 339, wherein the detection that the packet is associated with the first channel bandwidth or the second channel bandwidth is performed prior to decoding the header portion.

344. The method of claim 339, wherein the second channel bandwidth is twice as wide as the first channel bandwidth.

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

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

using at least one of a phase and an amplitude of at least one subcarrier in the plurality of long training symbols to determine that the packet is associated with one of a first channel bandwidth of X MHz and a second channel bandwidth of 2X MHz, wherein X is a number greater than 0,

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

346. The method of claim 345, wherein subcarrier indices for receiving a plurality of header information bits in the one or more overlapped frequency regions do not match in the first and second channel bandwidths, wherein the subcarrier indices determine an order in which the plurality of header information bits are mapped to subcarriers.

347. The method of claim 345, wherein the header portion indicates a recipient of the packet.

348. The method of claim 345, wherein the wireless OFDM transceiver supports IEEE 802.11 protocols.

349. The method of claim 345, wherein the determination that the packet is associated with the first channel bandwidth or the second channel bandwidth is performed prior to decoding the header portion.