Patent ID: 8301162

Claim:
A communication system comprising: one or more transceiver units of a first type; a data store accessible to each transceiver unit of the first type; two or more transceiver units of a second type, the transceiver units of a second type being capable of communicating with the transceiver units of the first type, and each transceiver unit of the second type comprising a local frequency reference unit on which the frequency of signals transmitted by it are dependent; wherein: at least one transceiver unit of the first type comprises: a frequency comparison unit configured to make a comparison of the frequency of a signal received from a transceiver unit of the second type with a reference frequency and to form an offset signal representative of the offset between the frequency of the signal received from the transceiver unit of the second type with the reference frequency, and a feedback unit configured to update the data store with feedback data representative of the offset signal in respect of that transceiver unit of the second type; and each transceiver unit of the first type comprises a frequency adjustment unit configured to adjust a transmit and/or receive frequency of the at least one transceiver unit of the first type for communication with one of the transceiver units of the second type in accordance with feedback data stored in the data store in respect of that transceiver unit of the second type.