Patent ID: 7489624
Filing Date: 2009-02-10
Classification: G06F,H03M,H04B,H04H,H04J,H04K,H04L,H04M,H04N,H04W,Y02D

Abstract:
1. A method for a remote unit to acquire a frequency band for communication with a host unit in a multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system, the method comprising: using a multiple access scheme to establish simultaneous multipoint-to-point orthogonal frequency division multiplexing communication from a plurality of remote units to a host unit; tuning a first remote unit of the plurality of remote units to a frequency band; determining whether the frequency band is a valid frequency band for the first remote unit to communicate with the host unit based on a downstream signal from the host unit transmitted within the frequency band; when the frequency band is determined to be not valid for the first remote unit, tuning the first remote unit to another frequency band; when the frequency band is determined to be valid for the first remote unit, communicating on at least one orthogonal tone within the frequency band; and receiving an adjustment signal from the host unit, the adjustment signal instructing the first remote unit to adjust the timing of transmissions to improve orthogonality of an OFDM waveform received at the host unit; wherein determining whether the frequency band is a valid frequency band comprises tuning to a control channel within the frequency band and receiving a downstream signal from the host unit containing an identifier associated with the first remote unit.