TECHNICAL FIELD

The disclosed embodiments relate, in general, to wireless or wire-line communications and include methods and apparatus for flexible use of frequency bands or channels, although these are merely exemplary and non-limiting fields.

BACKGROUND

In a TV broadcasting system, a UHF band (a band in the 470862 MHz range), for example, is often used for high-power transmission via an antenna at a great height to cover a large area. As a result, the usual practice is that this band and even its guard bands will not be used for high-power broadcasting in the vicinities of the coverage area. These bands, however, may be re-used in the neighboring areas for relatively low-power transmission in a cellular system Since the antenna of a cellular base station is located high up above the ground clutter, the base station is vulnerable to high-level interference from the TV broadcast transmission if cellular uplink transmission is in one of these bands. Consequently, the use of a time-division duplex (TDD) system in these bands may not be viable. Using a traditional frequency-division duplex (FDD) system may also not be feasible since these bands may not have with a corresponding uplink band that is required for FDD operation.

SUMMARY

To utilize the broadcast bands for cellular communications as described above, a flexible method is needed to facilitate efficient use of radio resources. For example, one of the broadcast guard bands may be used for downlink transmission and the flexible method can enable the system to use an available band (e.g., one of the MMDS bands around 2.52.6 GHz) for UL transmission.

The flexible method can be used to effectively utilize the spectrum that may become available from the switch from analogue to digital TV broadcasting. The use of a traditional FDD system with fixed pairing of downlink and uplink bands may not be feasible since bands in this spectrum do not come as fixed pairs for FDD transmission. Although TDD systems are being considered, strictly synchronous transmission is required if adjacent bands are to be used which may prevent the use of multiple systems using different technologies or operators.

In one embodiment, a method of communicating by a mobile device in a wireless communications system is disclosed. The wireless communications system utilizes frequency bands for downlink (DL) transmission and frequency bands for uplink (UL) transmission, each frequency band having a center carrier frequency and an operation bandwidth. A DL signal is received via a first DL frequency band for DL transmission. The DL signal includes DL-UL frequency-band association information. The DL signal is decoded to obtain the DL-UL frequency-band association information. Based on the decoded DL-UL frequency-band association information, a first UL frequency band is determined for UL transmission. Radio-frequency (RF) circuitry of the mobile device is configured to operate in the first UL frequency band for UL transmission.

