Time and frequency slot allocation system and method
First Claim
1. A radio communication system comprising:
- a plurality of frequencies for transmission of communication signals;
a plurality of time slots on each frequency;
a plurality of first stations which transmit and receive communication signals on the time slots; and
at least one second station which assigns time slots on a first frequency to first stations which are to be communicated with by employing highest second station transmitter power levels and which assigns time slots on a second frequency to first stations which are to be communicated with by employing second station transmitter power levels which are lower than said highest second station transmitter power levels, wherein each time slot transmitted on said first frequency is transmitted at a higher power level than each time slot transmitted on said second frequency.
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Accused Products
Abstract
Radio communication systems employing time division multiple access (TDMA) on several frequency channels are disclosed. The base station transmitting powers can be reduced when communicating with nearby mobile stations while still permitting the base station to employ a constant transmitting power in all time slots. This can be accomplished by, for example, grouping mobile stations having similar transmit power requirements together and allocating such groups to time slots on a same frequency. In this way, the base station can transmit at a constant power for each time slot on a frequency and provide acceptable communication quality, but without unnecessarily wasting base station transmitter power by transmitting to mobile stations having widely divergent power requirements.
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Citations
22 Claims
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1. A radio communication system comprising:
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a plurality of frequencies for transmission of communication signals; a plurality of time slots on each frequency; a plurality of first stations which transmit and receive communication signals on the time slots; and at least one second station which assigns time slots on a first frequency to first stations which are to be communicated with by employing highest second station transmitter power levels and which assigns time slots on a second frequency to first stations which are to be communicated with by employing second station transmitter power levels which are lower than said highest second station transmitter power levels, wherein each time slot transmitted on said first frequency is transmitted at a higher power level than each time slot transmitted on said second frequency. - View Dependent Claims (2, 3)
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4. A radio communication system comprising:
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a plurality of frequencies available for transmission of communication signals; a plurality of time slots on each frequency; a plurality of first stations which transmit and receive communication signals on the time slots; and at least one second station which sorts the first stations into groups requiring similar second station transmitting power and allocates a unique frequency to each group and a unique time slot to each first station in each group, whereby time slots allocated to a same frequency by said at least one second station are associated with a same second station transmitting power. - View Dependent Claims (5)
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6. A radio communication system comprising:
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a plurality of frequencies available for transmission of communication signals; a plurality of time slots on each frequency, wherein times slots on a common frequency are associated with a common second station transmitting power; a plurality of first stations which transmit and receive communication signals on the time slots; and at least one said second station comprising; a plurality of transmitters and an antenna system for transmitting communication signals to the first stations; a plurality of receivers for receiving communication signals from the first stations; a calling channel transmitter for transmitting a channel assignment message to the first stations; a random access receiver for receiving a random access message from one of the first stations and for measuring a quality and a signal strength of the random access message; a station controller for i) receiving the random access message, random access message quality, and random access message signal strength from the random access receiver and for estimating a transmitting power necessary to communicate with one of the first stations based on the random access message, random access message quality, and random access message signal strength;
for ii) selecting a frequency having an unallocated time slot for said one of said first stations based on the estimated transmitting power;
for iii) composing a channel assignment message; and
for iv) sending the channel assignment message to said one of said first stations via the calling channel transmitter. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A method for assigning time slots and frequencies in a radio communication system comprising the steps of:
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grouping together a first plurality of remote stations having a highest required base station transmission power; grouping together a second plurality of remote stations each of which has a lower required base station transmission power than any of said first plurality of remote stations; allocating each of said first plurality of remote stations to a plurality of time slots on a first frequency, each of said times slots associated with said first frequency thereby being associated with said highest required base station transmission power; and allocating each of said second remote stations to a plurality of time slots on a second frequency, each of said time slots associated with said second frequency thereby being associated with said lower required base station transmission power. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method of optimizing the allocation of time slots and frequencies for supporting two-way radio communication between a base station and a plurality of remote stations comprising:
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sending commands from said base station to said remote stations to use a higher or lower transmission power level in order to maintain a desired signal quality at said base station; continuously estimating path loss between each of said remote stations and said base station based on the strength of the signals communicated between said base and remote stations and commanded power level; sorting said remote stations according to said path loss values into an ordered list; and grouping neighboring remote stations in said list to use time slots on the same frequency, wherein time slots sharing the same frequency are all associated with a same base station transmitting power. - View Dependent Claims (20, 21, 22)
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Specification