Range extension mode for WiFi

Patent metadata

Field	Value
Publication number	US-9712358-B2
Application number	US-201414523678-A
Country	US
Kind code	B2
Filing date	Oct 24, 2014
Priority date	Oct 25, 2013
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A method for generating a physical layer (PHY) data unit for transmission via a communication channel is described where the PHY data unit conforms to a first communication protocol. Orthogonal frequency division multiplexing (OFDM) symbols for a data field of the PHY data unit are generated according to a range extension coding scheme that corresponds to a range extension mode of the first communication protocol. A preamble of the PHY data unit is generated, the preamble having i) a first portion that indicates a duration of the PHY data unit and ii) a second portion that indicates whether at least some OFDM symbols of the data field are generated according to the range extension coding scheme. The first portion of the preamble is formatted such that the first portion of the preamble is decodable by a receiver device that conforms to a second communication protocol, but does not conform to the first communication protocol, to determine the duration of the PHY data unit based on the first portion of the preamble. The PHY data unit is generated to include the preamble and the data field.

First claim

What is claimed is:

1. A method for generating a physical layer (PHY) data unit for transmission via a communication channel, the PHY data unit conforming to a first communication protocol, the method comprising:
generating, by a first communication device, orthogonal frequency division multiplexing (OFDM) symbols for a data field of the PHY data unit according to a range extension coding scheme that corresponds to a range extension mode of the first communication protocol;
generating, by the first communication device, a preamble of the PHY data unit, the preamble having i) a first portion that indicates a duration of the PHY data unit and ii) a second portion that indicates whether at least some OFDM symbols of the data field are generated according to the range extension coding scheme, the first portion of the preamble being formatted such that the first portion of the preamble is decodable by a receiver device that conforms to a second communication protocol, but does not conform to the first communication protocol, to determine the duration of the PHY data unit based on the first portion of the preamble;
generating, by the first communication device, the PHY data unit to include the preamble and the data field; and
causing the PHY data unit to be transmitted from the first communication device to a second communication device;
wherein:
generating the preamble comprises generating OFDM symbols for the second portion of the preamble that include i) a non-legacy signal field, and ii) a copy of the non-legacy signal field, wherein the copy of the non-legacy signal field indicates that the at least some OFDM symbols of the data field are generated according to the range extension coding scheme;
generating the preamble further comprises i) generating the first portion of the preamble, and ii) generating the second portion of the preamble; and
generating the first portion of the preamble comprises generating a first legacy signal field for the PHY data unit according to the second communication protocol and generating a second legacy signal field as a copy of the first legacy signal field.

2. The method of claim 1 , wherein generating the OFDM symbols for the data field of the PHY data unit according to the range extension coding scheme comprises:
encoding a plurality of information bits, to be included in the PHY data field, using a forward error correction (FEC) encoder to obtain a plurality of encoded bits;
mapping the plurality of encoded bits to a plurality of constellation symbols;
generating the OFDM symbols to include the plurality of constellation symbols; and
wherein the method further comprises performing one of:
i) encoding the plurality of information bits according to a block coding scheme,
ii) encoding the plurality of encoded bits according to the block coding scheme, or
iii) encoding the plurality of constellation symbols according to the block coding scheme.

3. The method of claim 1 , wherein generating the OFDM symbols for the data field of the PHY data unit according to the range extension coding scheme comprises:
generating the OFDM symbols for the data field to include a plurality of constellation symbols in a first bandwidth portion of a channel bandwidth and a copy of the plurality of constellation symbols in a second bandwidth portion of the channel bandwidth, wherein the first bandwidth portion and the second bandwidth portion have a same bandwidth.

4. The method of claim 3 , wherein generating the OFDM symbols for the data field comprises generating the copy of the plurality of constellation symbols to include a predetermined phase shift.

5. The method of claim 3 , wherein:
the OFDM symbols for the data field comprise first OFDM symbols;
generating the preamble includes generating the second portion of the preamble;
generating the second portion of the preamble comprises:
generating second OFDM symbols for i) a short training field according to the first communication protocol and ii) at least one copy of the short training field, and
generating third OFDM symbols for i) a long training field according to the first communication protocol and ii) at least one copy of the long training field; and

the first OFDM symbols, the second OFDM symbols, and the third OFDM symbols have a same tone plan that is distinct from a tone plan for the first portion of the preamble.

6. The method of claim 1 , wherein causing the PHY data unit to be transmitted from the first communication device to the second communication device comprises transmitting at least the first portion of the preamble with a transmission power boost as compared to the data field to increase a decoding range of the first portion of the preamble.

7. The method of claim 1 , wherein the first legacy signal field and the second legacy signal field indicate that the duration of the PHY data unit is a predetermined duration, wherein the second signal field is usable by a receiver device that conforms to the first communication protocol as a supplemental training field.

8. The method of claim 1 , wherein generating the PHY data unit to include the preamble and the data field comprises generating the PHY data unit to include a double guard interval according to the second communication protocol followed by the first legacy signal field and the second legacy signal field, without a guard interval between the first legacy signal field and the second legacy signal field.

9. The method of claim 1 , wherein the first legacy signal field and the second legacy signal field are decodable in combination by a receiver device that conforms to the first communication protocol to increase a decoding reliability of the first legacy signal field and the second legacy signal field.

10. The method of claim 1 , wherein:
the first portion of the preamble includes i) a legacy short training field that conforms to the second communication protocol, ii) a non-legacy long training field, and iii) a legacy signal field that conforms to the second communication protocol;
the second portion of the preamble does not include any training fields;
the method further comprises:
generating, by the first communication device, a first plurality of constellation symbols for the legacy short training field using a legacy tone plan that conforms to the second communication protocol,
generating, by the first communication device, a second plurality of constellation symbols for the non-legacy long training field using a non-legacy tone plan; and

generating the OFDM symbols for the data field comprises generating a third plurality of constellation symbols using the non-legacy tone plan.

11. The method of claim 1 , wherein generating the preamble comprises:
generating OFDM symbols for the first portion of the preamble as a legacy preamble, using a normal guard interval, that conforms to the second communication protocol; and
generating the OFDM symbols for the second portion of the preamble using a long guard interval.

12. The method of claim 11 , wherein generating the OFDM symbols for the second portion of the preamble comprises:
generating OFDM symbols for the non-legacy signal field and a non-legacy short training field using the normal guard interval; and
generating OFDM symbols for a non-legacy long training field using the long guard interval.

13. The method of claim 11 , wherein generating OFDM symbols for the second portion of the preamble comprises:
generating OFDM symbols for a legacy signal field using the normal guard interval; and
generating OFDM symbols for the non-legacy signal field using the long guard interval.

14. The method of claim 11

Assignees

• Marvell World Trade Ltd

Inventors

• Zhang Hongyuan
• Lou Hui-Ling
• Yong Su Khiong

Classifications

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title

• H04W52/286

  during data packet transmission, e.g. high speed packet access [HSPA] · CPC title

• H04J11/00

  Orthogonal multiplex systems, {e.g. using WALSH codes}(H04J13/00 takes precedence) · CPC title

• H04L27/2698

  double density OFDM/OQAM system, e.g. OFDM/OQAM-IOTA system · CPC title

• H04L1/0057

  Block codes (H04L1/0061, H04L1/0064 take precedence) · CPC title