Method and system to detect packets of different formats in a receiver
A method and system of communicating packets and detecting packets are disclosed. In a first aspect, the method and system comprise enabling the detection of a very high throughput (VHT) signal field. The VHT signal field is distinguishable from other signal fields, wherein the VHT signal field allows for a backward compatibility with other devices. In a second aspect, the method and system comprise initializing the device to be in receive mode and receiving at least one signal field symbol and detecting the presence of additional signal field symbols. The method and system further include distinguishing a very high throughput (VHT) signal field from other signal field symbols and decoding the VHT signal field parameters uniquely describing the VHT packet format.
1. A method for detecting packets of different formats in a receiver comprising:
receiving at least one signal field symbol;
detecting the presence of additional signal field symbols;
distinguishing a very high throughput (VHT) signal field from other signal field symbols by summing a difference in power between real components and imaginary components of rotated binary phase shift keying (BPSK) symbols that are on alternating subcarriers, odd and even, within the VHT signal field, wherein the VHT signal field allows for a backward compatibility with other devices; and
decoding VHT signal field parameters to uniquely describe VHT packet format.
2. The method of claim 1 wherein the rotated BPSK symbols are rotated 90 degrees.
3. The method of claim 2 wherein the rotated BPSK symbols are on the even alternating subcarriers.
4. The method of claim 2 wherein the rotated BPSK symbols are on the odd alternating subcarriers.
5. The method of claim 1 wherein the imaginary components are large relative to the real components if the VHT signal field comprises 90 degree rotated BPSK symbols.
6. The method of claim 1 wherein summing the difference comprises a summation wherein the summation comprises:
∑
i
,
even
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I
i
2
-
Q
i
2
)
-
∑
k
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odd
Nsc
(
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k
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)
.
7. A system for detecting packets of different formats in a receiver comprising:
a processor; and
a memory device coupled to the processor, said memory device storing an application which, when executed by the processor, causes the processor to:
receive at least one signal field symbol;
detect the presence of additional signal field symbols;
distinguish a very high throughput (VHT) signal field from other signal field symbols by summing a difference in power between real components and imaginary components of rotated binary phase shift keying (BPSK) symbols that are on alternating subcarriers, odd and even, within the VHT signal field, wherein the VHT signal field allows for a backward compatibility with other devices; and
decode VHT signal field parameters to uniquely describe VHT packet format.
8. The system of claim 7 wherein the rotated BPSK symbols are rotated 90 degrees.
9. The system of claim 8 wherein the rotated BPSK symbols are on the even alternating subcarriers.
10. The system of claim 8 wherein the rotated BPSK symbols are on the odd alternating subcarriers.
11. The system of claim 7 wherein the imaginary components are large relative to the real components if the VHT signal field comprises 90 degree rotated BPSK symbols.
12. The system of claim 7 wherein summing the difference comprises a summation wherein the summation comprises:
∑
i
,
even
Nsc
(
I
i
2
-
Q
i
2
)
-
∑
k
,
odd
Nsc
(
I
k
2
-
Q
k
2
)
.