Patent ID: 7856068
Filing Date: 2010-12-21
Classification: H04B,H04L

Abstract:
1. A multi input multi output (MIMO) system for transmitting and receiving packets that include a preamble comprising: a receiver; and a nested preamble, included in said packets, said receiver being responsive to the nested preamble, said nested preamble having poly-carrier long training sequence (LTS) and signal field (SIG) for training said receiver, at least some of said packets being transmitted using the modulation scheme of a wireless local area network (WLAN) standard, said nested preamble format for allowing said receiver to use one or more receiver antennas to interpret said LTS and said SIG to increase the efficiency of said MIMO system, said nested preamble including a second poly-carrier long training sequence (LTS) having double symbol length to provide per-tone based channel estimation, said nested preamble further including a second short training sequence (STS-A) having a single symbol length to align symbol boundary for simplicity, said STS-A being sent for adjusting automatic gain control (AGC), said second poly-carrier long training sequence (LTS) for providing transmit (TX) beamforming capability to focus energy in a desired direction.