Patent ID: 8144683

Claim:
A method of receiving a mixed mode packet, the mixed mode packet including a legacy header and a high throughput (HT) header, the method comprising: receiving a packet; determining whether a predetermined phase rotation in the packet is detected; after detecting the predetermined phase rotation, which identifies the packet as a mixed mode packet, removing at least one cyclic shifting delay (CSD) from a plurality of fields of the mixed mode packet from each chain, wherein removing includes computing an “over the air” (OTA) channel value; after CSD removal, determining a timing offset of the mixed mode packet based on the OTA channel value; and after determining the timing offset, compensating for the timing offset, thereby facilitating accurate decoding of the mixed mode packet, wherein computing the OTA channel value includes: computing a preliminary estimated “over the air” (OTA) channel Ĥ1 OTA (k) using a first equation: H ^ ⁢ 1 OTA ⁢ ( k ) = H ^ ⁡ ( k ) ⁢ Q CSD - 1 = H OTA ⁡ ( k ) ⁢ exp ⁡ ( j2πτ ⁢ k N ) , wherein Ĥ is an estimated channel, Q CSD is a matrix describing CSD, H OTA is an OTA channel, exp ⁡ ( j2πτ ⁢ k N ) is a timing error, and τ is a timing offset.