Abstract: A cluster management module will receive a transmission from a subscriber module and estimate a range for a subscriber module based on the received transmission. A receive power for the transmission will be obtained and a transmit power for the subscriber module will be determined based on the range of the subscriber module and the receive power of the transmission. Network access will be allowed or denied based on the transmit power of the subscriber module. In a second embodiment, an azimuth angle is additionally determined from the received transmission, and an approximate location of the subscriber module is determined. Network access is then allowed or denied based on the transmit power of the subscriber module and additionally based on the location of the subscriber module.

Abstract: A method and apparatus for allowing communication units to utilize non-licensed spectrum is provided herein. In particular, when a radio determines a need to transmit within non-licensed spectrum, the radio searches for a beacon being transmitted. The beacon identifies a priority of the current user of the non-licensed spectrum. If the radio's priority is higher than the current user of the non-licensed spectrum, or if no beacon is heard, the radio may begin transmitting within the non-licensed spectrum. As part of the radio's transmission, a beacon will be broadcast by the radio identifying the radio's priority.

Abstract: The presence of the non-television transmission within a channel is used to indicate that secondary non-licensed usage of the channel is permitted. Specifically, if secondary users incorporate the means to identify the unique modulation signature of the secondary user, decoding of a beacon signal may not be necessary. With the above in mind, a radio will be prevented from transmitting within a frequency band when no transmission within the licensed spectrum is currently taking place; the licensee is currently transmitting on the spectrum (e.g., television transmissions are taking place utilizing the spectrum, or the radio cannot sense the presence of a data channel (beacon).

Abstract: A switching amplifier generates noise at its switching frequency and harmonics thereof. The noise at these harmonics, for an audio amplifier, will be generated with significant amplitude in the AM band. Thus, an AM tuner will experience interference problems if the tuner frequency is sufficiently close to one of these harmonics. To avoid this problem the switching frequency of the switching amplifier is chosen based on the tuner frequency. Thus, the switching frequency is chosen to avoid having harmonics at or too near the chosen tuner frequency. The switching amplifier is disabled when the tuner is in seek or scan mode. Instead of using the tuner frequency to determine what switching frequency should be used to avoid interference, the interference can be detected directly to cause a change in the switching frequency and thus remove the interference.

Abstract: A switching amplifier generates noise at its switching frequency and harmonics thereof. The noise at these harmonics, for an audio amplifier, will be generated with significant amplitude in the AM band. Thus, an AM tuner will experience interference problems if the tuner frequency is sufficiently close to one of these harmonics. To avoid this problem the switching frequency of the switching amplifier is chosen based on the tuner frequency. Thus, the switching frequency is chosen to avoid having harmonics at or too near the chosen tuner frequency. The switching amplifier is disabled when the tuner is in seek or scan mode. Instead of using the tuner frequency to determine what switching frequency should be used to avoid interference, the interference can be detected directly to cause a change in the switching frequency and thus remove the interference.