Staggered frequency hopping cellular radio system
First Claim
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1. A method for radio communications between a plurality of base stations and a plurality of mobile stations in a cellular radio telephone system comprising the steps of:
- varying a frequency used for each mobile-base communication link at regular intervals according to a pseudorandom pattern, such that each mobile station communicating with a base station in a given cell changes frequency at the same time; and
varying frequencies used by mobile stations in surrounding cells at offset times, wherein such offset times are a function of cell position relative to said given cell.
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Abstract
A communication system having a frequency hopping scheme which provides increased interferer diversity without increased system delay is disclosed. The frequency hopping scheme includes providing a staggered offset period between hops of neighboring or adjacent base stations so as to create additional interference situations (diversity).
119 Citations
26 Claims
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1. A method for radio communications between a plurality of base stations and a plurality of mobile stations in a cellular radio telephone system comprising the steps of:
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varying a frequency used for each mobile-base communication link at regular intervals according to a pseudorandom pattern, such that each mobile station communicating with a base station in a given cell changes frequency at the same time; and varying frequencies used by mobile stations in surrounding cells at offset times, wherein such offset times are a function of cell position relative to said given cell. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for radio communications between a plurality of base stations and a plurality of mobile stations in a cellular radio telephone system using time division multiple access combined with frequency hopping comprising the steps of:
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dividing TDMA frame periods into a number of time slots; allocating the time slots in each frame period for communication between different mobile stations in a first group of mobile stations and a first base station; varying a frequency for transmission or reception of the time slots in a frame period from frame period to frame period according to a pseudorandom pattern; and offsetting TDMA frame periods used by surrounding base stations in time by a number of fractions of a time slot that is a function of base station position relative to said first base station. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for radio communications between a plurality of base stations and a plurality of mobile stations in a cellular radio telephone system comprising the steps of:
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encoding speech signals, using an error-correcting code, into blocks of data symbols for transmission; dispersing said blocks of symbols over a number of hops for transmission and including at least one known symbol pattern in each hop and a number of guard symbols at a beginning and end of each hop; selecting frequencies sequentially for each hop according to a pseudorandom sequence; transmitting said hops sequentially between a mobile station and a base station by smoothly increasing a transmit power from zero while said guard symbols at the beginning of a hop are transmitted and smoothly reducing the transmit power to zero while said guard symbols at the end of a hop are transmitted to form a guard period of zero transmission between hops; and selecting timing offsets between base stations in different cells such that said guard periods of transmissions in a first cell coincide with transmissions of said at least one known symbol pattern in a second cell.
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14. A system for radio communications between a plurality of base stations and a plurality of mobile stations comprising:
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means for varying a frequency used for each mobile-base communication link at regular intervals according to a pseudorandom pattern, such that each mobile station communicating with a base station in a given cell changes frequency at the same time; and means for varying frequencies used by mobile stations in surrounding cells at offset times, wherein said offset times are a function of cell position relative to said given cell. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A system for radio communications between a plurality of base stations and a plurality of mobile stations in a cellular radio telephone system using time division multiple access combined with frequency hopping comprising:
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means for dividing TDMA frame periods into a number of time slots; means for allocating the time slots in each frame for communication between different mobile stations in a first group of mobile stations and a first base station; and means for varying a frequency for transmission or reception of the time slots in a frame period from frame period to frame period according to a pseudorandom pattern, wherein TDMA frame periods used by surrounding base stations are offset in time by a number of fractions of a time slot that is a function of base station position relative to said first base station. - View Dependent Claims (21, 22, 23, 24, 25)
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26. A system for radio communications between a plurality of base stations and a plurality of mobile stations in a cellular radio telephone system comprising:
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means for encoding speech signals, using an error-correcting code, into blocks of data symbols for transmission; means for dispersing said block of symbols over a number of hops for transmission and including at least one known symbol pattern in each hop and a number of guard symbols at the beginning and end of each hop; means for selecting frequencies sequentially for each hop according to a pseudorandom sequence; means for transmitting said hops sequentially between a mobile station and a base station by smoothly increasing a transmit power from ;
zero while said guard symbols at a beginning of a hop are transmitted and smoothly reducing the transmit power to zero while said guard symbols at the end of a hop are transmitted to form a guard period of zero transmission between hops; andmeans for selecting timing offsets between the stations in different cells such that said inter-hop guard periods of transmissions in a first cell coincide with transmissions of said at least one known symbol pattern in a second cell.
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Specification