Transmission time delay measurement at transmission paths in a radio telecommunication system
First Claim
1. A method for evaluating transmission time delays at transmission paths in a radio telecommunication system between a central interface unit and a plurality of radio access units operatively connected to said central interface unit, wherein said radio access units transmit radio signals to and receive radio signals from adjacent radio access units relative to their own time base, wherein said transmission time delays are evaluated from time differences between a time of transmission of a radio signal by a radio access unit relative to the time base of said radio access unit and a time of reception of said radio signal by an adjacent radio access unit relative to the time base of said adjacent radio access unit, said time bases being controlled by said central interface unit and lagging said transmission time delays, said method comprises the steps of:
- a) transmitting a first radio signal from a first of said plurality of radio access units at a first time relative to the time base of said first radio access unit;
b) receiving said first radio signal by a second of said plurality of radio access units at a second time relative to the time base of said second radio access unit;
c) transmitting a second radio signal from said second radio access unit at a third time relative to the time base of said second radio access unit;
d) receiving said second radio signal by said first radio access unit at a fourth time relative to the time base of said first radio access unit; and
e) calculating from said first, second, third and fourth time a relative transmission time delay between the transmission paths from said central control unit to each of said first and second radio access units.
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Accused Products
Abstract
In a cordless (e.g. DECT) or cellular radio telecommunication system (1), comprising a plurality of radio access units (3) operatively connecting to a central interface unit (2), transmission time delays at transmission paths (11, 12, 13) between the central interface unit (2) and the radio access units (3) are established from time differences measured between the transmission and reception of radio signals by adjacent radio access units (3). Synchronous operation at the air interface (9) is obtained by compensation of the time delays at the transmission paths (11, 12, 13).
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Citations
19 Claims
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1. A method for evaluating transmission time delays at transmission paths in a radio telecommunication system between a central interface unit and a plurality of radio access units operatively connected to said central interface unit, wherein said radio access units transmit radio signals to and receive radio signals from adjacent radio access units relative to their own time base, wherein said transmission time delays are evaluated from time differences between a time of transmission of a radio signal by a radio access unit relative to the time base of said radio access unit and a time of reception of said radio signal by an adjacent radio access unit relative to the time base of said adjacent radio access unit, said time bases being controlled by said central interface unit and lagging said transmission time delays, said method comprises the steps of:
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a) transmitting a first radio signal from a first of said plurality of radio access units at a first time relative to the time base of said first radio access unit;
b) receiving said first radio signal by a second of said plurality of radio access units at a second time relative to the time base of said second radio access unit;
c) transmitting a second radio signal from said second radio access unit at a third time relative to the time base of said second radio access unit;
d) receiving said second radio signal by said first radio access unit at a fourth time relative to the time base of said first radio access unit; and
e) calculating from said first, second, third and fourth time a relative transmission time delay between the transmission paths from said central control unit to each of said first and second radio access units. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A radio telecommunication system, comprising a plurality of radio access units operatively connected to a central interface unit, each radio access unit comprising transceiver means for transmitting and receiving radio signals to and from adjacent radio access units, and time base generator means providing a time base of said radio access unit, wherein said central interface unit comprises means for evaluating transmission time delays at transmission paths between said central interface unit and said plurality of radio access units from time differences between a time of transmission of a radio signal by a radio access unit relative to the time base of said radio access unit and a time of reception of said radio signal by an adjacent radio access unit relative to the time base of said adjacent radio access unit, said time base generator means being controlled by said central interface unit and lagging said transmission time delays said radio telecommunication system being arranged for:
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a) transmitting a first radio signal from a first of said plurality of radio access units at a first time relative to the time base of said first radio access unit;
b) receiving said first radio signal by a second of said plurality of radio access units at a second time relative to the time base of said second radio access unit;
c) transmitting a second radio signal from said second radio access unit at a third time relative to the time base of said second radio access unit;
d) receiving said second radio signal by said first radio access unit at a fourth time relative to the time base of said first radio access unit;
e) said radio telecommunication system further comprises means for calculating from said first, second, third and fourth time a relative transmission time delay between the transmission paths from said central control unit and to each of said first and second radio access units. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification