Abstract: Methods and systems for improving adjacent channel rejection performance in a wireless signal by a radio device in a mobile network. In one embodiment, a mobile radio network includes a first radio device (e.g., a subscriber), a second radio device, and a fixed radio apparatus (e.g., a base station or repeater). The first radio device receives a first channel signal having a first frequency offset with respect to a reference frequency. The first channel signal is associated with the second radio device. The first radio device measures the first frequency offset, determines a second frequency offset for a second channel signal, and transmits the second channel signal with the second frequency offset.

Abstract: A method and apparatus for simulcasting within a communication system is provided herein. During operation, each base site will be equipped with a plurality of radios capable of transmitting on various frequencies. Base sites within the communication system will be capable of communicating on a predetermined number of channels, which may differ among base sites. A number of channels will be shared by the base sites. When a simulcast is desired, the participants are located, and a common channel is determined for communication. Thus, call participant location information is used to determine the best channel to use to meet the group's coverage needs.

Abstract: Methods and systems for improving adjacent channel rejection performance in a wireless signal by a radio device in a mobile network. In one embodiment, a mobile radio network includes a first radio device (e.g., a subscriber), a second radio device, and a fixed radio apparatus (e.g., a base station or repeater). The first radio device receives a first channel signal having a first frequency offset with respect to a reference frequency. The first channel signal is associated with the second radio device. The first radio device measures the first frequency offset, determines a second frequency offset for a second channel signal, and transmits the second channel signal with the second frequency offset.

Abstract: A method and apparatus for simulcasting within a communication system is provided herein. During operation, each base site will be equipped with a plurality of radios capable of transmitting on various frequencies. Base sites within the communication system will be capable of communicating on a predetermined number of channels, which may differ among base sites. A number of channels will be shared by the base sites. When a simulcast is desired, the participants are located, and a common channel is determined for communication. Thus, call participant location information is used to determine the best channel to use to meet the group's coverage needs.

Abstract: Detection of a locomotive or other vehicle is enhanced by transmitting an RF alert signal from the vehicle when the vehicle approaches a heightened alert area such as a railroad crossing. The RF alert signal is received by communication unit(s) carried by pedestrian(s) or residing in vehicle(s) approaching the heightened alert area, thereby providing an alert that supplements train whistles, gates, horns or other warning mechanisms known in the art. The RF alert signal may also be transmitted to infrastructure devices such as logging devices. In one embodiment, the RF alert signal is transmitted from a locomotive upon detecting operation of a train whistle associated with the locomotive and/or coincident to receiving an external alert signal or automatic vehicle location (AVL) information indicating that the locomotive is near a heightened alert area.