Abstract: A method of channel estimation in a wireless orthogonal frequency division multiplexed (OFDM) communication system is disclosed. The method comprises receiving a signal in the time domain and applying a Fourier transform to the received signal to obtain a frequency domain signal including a plurality of sub-carriers. Then, the method requires estimating probabilities of coded bits for the plurality of frequency domain sub-carriers and performing channel coefficient estimation for the plurality of frequency domain sub-carriers using channel coefficient estimates for another of the plurality of frequency domain sub-carriers.

Abstract: A receiver (103) for receiving an Ultra Wide Band (UWB) signal comprises a receiver front end (105) coupled to symbol point correlators (107). The symbol point correlators (107) comprise a first plurality of correlators which generates correlated signal values around a first symbol decision point of a first symbol by correlating the received UWB signal with a local replica. The first plurality of correlators are time offset with respect to each other to generate first time offset correlated signal values. The time offsets are typically significantly less than the timing jitter of transmit and receive oscillators. The symbol point correlators (107) are coupled to a joint estimator (109) which determines a symbol value of the first symbol in response to the first time offset correlated signal values by joint detection of the symbol value and a time offset of the UWB signal. The invention may effectively reduce time jitter noise to a value determined by the relative time offset between the correlators.

Abstract: Apparatus for estimating carrier and clock frequency offsets in OFDM systems employs a maximun likelihood estimator operation on the demodulated signals. The invention has the benefit of low complexity and obviates the need for any requirement for a dedicated training channel.