Methods and apparatus for selecting between multiple carriers using a single receiver chain tuned to a single carrier

摘要

A communications system comprises a portable communications device and a first base station. The portable communications device includes i) a receiver antenna for receiving a signal including a first component and a second component; ii) a controllable filter coupled to the antenna for filtering the received signal and for passing signals in a selected one of a first frequency band and a second frequency band while discarding at least some frequencies included in the other one of the first and second frequency bands, iii) a first signal measurement device coupled to the controllable filter for performing a first signal measurement on the first signal component to generate a first signal quality indicator; iv) a second signal measurement device coupled to the controllable filter for performing a second signal measurement on the second signal component to generate a second signal quality indicator; v) a frequency band selection module for selecting between operating in the first frequency band and a second frequency band as a function of the first and second signal quality indicators and for generating a control signal used to control the one of the first and second frequency bands which will be passed by the controllable filer. The first and second signal components are within the selected one of the first and second frequency bands. The first signal component is associated with the first frequency band and the second signal component is associated with the second frequency bands. The base station is located in a communications cell and includes a first transmitter which primarily transmits in the first frequency band for transmitting the first signal component.