Frequency and channel hopping communication in a TDMA cellular mobile radio system
First Claim
1. A method for transmitting radio signals in a time division multiple access (TDMA) radiocommunication system comprising the steps of:
- providing first and second cells adjacent one another, each cell having respective first and second base stations;
allocating a first set and a second set of TDMA radio channels for usage by said first and second base stations, respectively, said first and second sets including substantially the same channels, said channels including timeslots organized into frames;
transmitting radio signals from said first base station, on no more than a maximum number of said timeslots in each frame, said maximum number being less than a total number of available timeslots assigned to said first set of radio channels; and
transmitting radio signals from said second base station, on no more than said maximum number of said timeslots in each frame.
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Abstract
According to method and apparatus for communication in a cellular TDMA mobile radio communication system with channel hopping, base and mobile stations transmit radio signal bursts in time slots of a plurality of radio channels in accordance with channel hopping schemes. All of the schemes used by a base and mobile stations in a cell are free from coincidence on any radio channel with any other of the schemes used for transmission within the same cell. A scheme used by a mobile station in one cell occasionally coincides on a radio channel with a scheme used by a mobile station in another cell. The major part of every channel shifting scheme used by a mobile station in a cell is free from coincidence on any radio channel with the major part of any channel hopping scheme used by a mobile station in another cell. The signal to interference ratio or other signal characteristics such as signal strength or bit error rate for signals received by mobile stations are estimated and compared, and the output power of stations are controlled. The existence of further possible channel hopping schemes in a cell, free from coincidence on every radio channel with every other of the channel hopping schemes already in use in that cell, is checked. When another connection to a particular mobile is desired and there is a possible mobile scheme free from coincidence, the desired connection is established using the possible channel hopping scheme in the cell, only if the estimated C/I for certain mobile stations involved in connections exceeds a minimum level.
138 Citations
22 Claims
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1. A method for transmitting radio signals in a time division multiple access (TDMA) radiocommunication system comprising the steps of:
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providing first and second cells adjacent one another, each cell having respective first and second base stations; allocating a first set and a second set of TDMA radio channels for usage by said first and second base stations, respectively, said first and second sets including substantially the same channels, said channels including timeslots organized into frames; transmitting radio signals from said first base station, on no more than a maximum number of said timeslots in each frame, said maximum number being less than a total number of available timeslots assigned to said first set of radio channels; and transmitting radio signals from said second base station, on no more than said maximum number of said timeslots in each frame. - View Dependent Claims (2)
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3. A TDMA radiocommunication system including first and second cells adjacent one another, said system comprising:
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first and second base stations disposed in said first and second cells, respectively; a first set and a second set of TDMA radio channels for usage by said first and second base stations, respectively, said first and second sets including substantially the same channels, said channels including timeslots organized into frames; a first transmitter, in said first base station, which transmits signals on up to a maximum number of said timeslots in each frame, said maximum number being less than a total number of available timeslots assigned to said first set of radio channels; and a second transmitter, in said second base station, which transmits signals on up to said maximum number of said timeslots in each frame. - View Dependent Claims (4)
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5. A method for transmitting radio signals associated with connections in a time division multiple access (TDMA) radiocommunication system comprising the steps of:
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providing first and second cells adjacent one another, each cell having respective first and second base stations; allocating a first set and second set of TDMA radio channels for usage by said first and second base stations, respectively, said first and second sets simultaneously including substantially the same channels; transmitting radio signals from a transmitter to remote stations in said first and second cells using said first and second sets of radio channels, respectively; and limiting an average number of simultaneous connections in said first and second cells to be substantially less than an average number of timeslots on said radio channels in said first and second sets, respectively. - View Dependent Claims (6, 7, 8)
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9. A radiocommunication system including first and second cells adjacent one another, said system comprising:
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a first set and second set of TDMA radio channels for usage by said first and second base stations, respectively, said first and second sets simultaneously including substantially the same channels; first and second transmitters for transmitting signals to remote stations in said first and second cells using said first and second sets of radio channels, respectively; and means for limiting an average number of simultaneous connections in said first and second cells to be substantially less than an average number of timeslots on said radio channels in said first and second sets, respectively. - View Dependent Claims (10, 11, 12)
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13. A method for transmitting radio signals in a time division multiple access (TDMA) radiocommunication system comprising the steps of:
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providing first and second cells adjacent one another, each cell having respective first and second base stations; allocating a first set and second set of TDMA radio channels for usage by said first and second base stations, respectively, said first and second sets including substantially the same channels; estimating signal-to-interference ratios for signals received from mobile stations in the first cell in said first base station and the second cell in said second base station; comparing the estimated signal-to-interference ratios with a desired signal-to-interference ratio; identifying one of said TDMA radio channels in said first set which is currently unused in the first cell; and establishing one or more connections between said mobile stations and one of said first base station and said second base station using said one of said TDMA radio channels in said first set if said estimated signal-to-interference ratios based upon mobile stations in at least one of said first and second cells exceed the desired signal-to-interference ratio. - View Dependent Claims (14, 15, 16, 17)
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18. A time division multiple access (TDMA) radiocommunication system comprising:
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first and second cells adjacent one another, each cell having respective first and second base stations; a first set and second set of TDMA radio channels for usage by said first and second base stations, respectively, said first and second sets including substantially the same channels; means, disposed in said first and second base stations, for estimating signal-to-interference ratios for signals received from mobile stations in the first cell and in the second cell, respectively; means for comparing the estimated signal-to-interference ratios with a desired signal-to-interference ratio; means for establishing one or more connections between said mobile stations and one of said first base station and said second base station using a currently unused one of said TDMA radio channels in said first set if estimated signal-to-interference ratios based upon certain mobile stations exceed said desired signal-to-interference ratio. - View Dependent Claims (19, 20, 21, 22)
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Specification