Method and apparatus for dynamically grouping transmitters for message transmission in a communication system

A communication system for dynamically selecting transmitters for message transmission, the communication system comprising:

• the transmitters for sending, at a known time and carrier frequency, transmission signals;
• a portable messaging unit (PMU) for receiving at the known time and carrier frequency the transmission signals, calculating signal strengths of the transmission signals, and transmitting a signal indicative of the signal strengths;
• and
• a controller for receiving the signal, determining therefrom carrier-to-interference (C/I) values indicative of relative strengths of the transmission signals received by the PMU prior to message delivery to the PMU, and determining a selected transmitter for transmitting a message to the PMU, the selected transmitter associated with a lowest C/I value that is chosen from the C/I values and that exceeds a C/I threshold value.

A portable messaging unit (PMU) for receiving signals, the PMU comprising:

• a transceiver for receiving, at a known time and carrier frequency, transmission signals transmitted by transmitters;
• calculating means coupled to the transceiver for calculating carrier-to-interference (C/I) values indicative of relative strengths of the transmission signals;
• and
• determining means coupled to the calculating means for determining, prior to message delivery to the PMU, a selected transmitter for transmitting a message to the PMU, the selected transmitter associated with a lowest C/I value that is chosen from the C/I values and that exceeds a C/I threshold value,
• wherein the transceiver transmits a signal indicative of the selected transmitter for subsequent use in transmitting the message to the PMU.

A controller for dynamically grouping transmitters for message transmission to portable messaging units (PMUs), the controller comprising:

• a receiver for receiving a first signal indicative of first signal strengths of transmission signals received by a first PMU and a second signal indicative of second signal strengths of transmission signals received by a second PMU;
• a calculator coupled to the receiver for computing first carrier-to-interference (C/I) values indicative of relative strengths of the transmission signals received by the first PMU and for computing second C/I values indicative of relative strengths of the transmission signals received by the second PMU;
• and
• a sender coupled to the calculator for determining, from the first C/I values and prior to message delivery to the first and second PMUs, a first selected transmitter and a first reuse factor for transmitting a first message to the first PMU, the first reuse factor included in a number of reuse factors used by the controller for grouping the transmitters for message delivery, and for determining, from the second C/I values, a second selected transmitter and a second reuse factor for transmitting a second message to the second PMU, the second reuse factor also included in the number of reuse factors.