EP0578506A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Transmission timing control in a cellular TDMA mobile communication system
Assignee: NEC Corp
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Filing: 1993-07-09
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Granted: —
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Expires: 2013-07-09
Abstract
Abstract In each of radio base stations of a cellular mobile communication network in which a mobile station is communicative with the radio base stations through a time division multiplex radio link, a transmitter/receiver (33) serves as a synchronization system in cooperation with a base station control utit (35) to synchronize a down-link radio signal generated from a transmission frame generator (51) at a transmission time instant with a like down-link radio signal transmitted from a different one of the radio base stations. The synchronazation system comprises a received frame regenerator (65) for detecting a recetion time instant of one of frames of an up-link radio signal directed from the mobile station to the different station. A timing controller (53) calculates a time difference between tha transmission and the reception time instants. Controlled by the control unit in accordance with the time difference, the timing controller controls, in turn, the transmission time instant. Preferably, the time difference is stored in a memory (67) and read out by the control unit when the received frame regenerator receives another of the up-link frames that next follows the above-mentioned one up-link frame.
Inventors
- 👤 Tadao c/o NEC CORPORATION Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 19:22
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/24; H04B7/26; H04B7/2662; H04B7/2671; H04B7/2678; H04B7/2687
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
113 words
A synchronization system for use in a cellular digital mobile communication network comprising a plurality of radio base stations and a mobile station communicative with said radio base stations through a time division multiplex radio communication link, wherein said synchronization system comprises in each radio base station: receiving means for receiving an up-link radio signal directed from said mobile station to a different one of said radio base stations to measure a reception time instant of reception of said up-link radio signal; and adjusting means for adjusting, based on said reception time instant, a transmission time instant of a down-link radio signal transmitted by said each radio base station towards said mobile station.
Claim 2
Dependent Claim
173 words
A synchronization system as claimed in Claim 1, said up-link radio signal comprising up-link frames, said down-link radio signal comprising down-link frames, wherein: said receiving means receives said up-link frames as received frames to produce a first reception timing signal representative of said reception time instant in response to a first one of said received frames; said adjusting means comprising: a base station control unit for producing transmission timing pulses indicative of said transmission time instant; and timing adjusting means supplied with said transmission timing pulses and said first reception timing signal for calculating a time difference between said reception time instant and a time instant indicated- by one of said transmission timing pulses that is produced nearest in time to said reception time instant; said receiving means producing a second reception timing signal in response to a second one of said received frames; said timing adjusting means adjusting said transmission timing pulses if said time difference is not shorter than a predetermined time interval upon production of said second reception timing signal.
Claim 3
Dependent Claim
173 words
A synchronazation system as claimed in Claim 1, said up-link radio signal comprising up-link frames, said down-link radio signal comprising down-link frames, wherein: said receiving means receives said up-link frames as received frames to produce a first reception timing signal representative of said reception time instant in response to a first one of said received frames; said adjusting means comprising: a base station control unit for producing transmission timing pulses indicative of said transmission time instant; and timing adjusting means supplied with said transmission timing pulses and said first reception timing signal for calculating a time difference between said reception time instant and a time instant indicated by one of said transmission timing pulses that is produced nearest in time to said reception time instant; said receiving means producing a second reception timing signal in response to a second one of said received frames; said timing adjusting means leaving said transmission timing pulses untouched if said time difference is shorter than a predetermined time interval upon production of said second reception timing signal.
Claim 4
Dependent Claim
31 words
A synchronization system as claimed in Claim 3, each of said down-link frames being preceded by a guard time, wherein said predetermined time interval is not longer than said guard time.
Claim 5
Dependent Claim
104 words
A synchronization system as claimed in Claim 2, wherein said timing adjusting means comprises: a timing controller supplied with said transmission timing pulses and said first reception timing signal to calculate said time difference; and a memory loaded with said time difference; said base station control unit being supplied with said second reception timing signal to read said time difference from said memory and to produce a timing adjust signal if said predetermined time interval is not shorter than the time difference read by said second reception timing signal; said timing controller adjusting said transmission timing pulses in response to said timing adjust signal.
Claim 6
Dependent Claim
64 words
A synchronization system as claimed in Claim 5, each down-link frame comprising a plurality of time slots having a slot length in common, wherein: said base station control unit makes said timing adjust signal indicate a difference calculated by subtracting said time difference from said slot length; said timing controller delaying said transmission timing pulses by the difference indicated by said timing adjust signal.
Claim 7
Dependent Claim
56 words
A synchronisation system as claimed in Claim 5, each down-link frame comprising a plurality of time slots having a slot length in common, wherein: said base station control unit makes said timing adjust signal indicate a sum of said slot lenght and said time difference; said timing controller advancing said transmission timing pulses by said sum.
Claim 8
Dependent Claim
31 words
A synchronization system as claimed in Claim 6 or 7, each slot length being preceded by a guard time, wherein said predetermined time interval is not longer than said guard time.
Claim 9
Dependent Claim
91 words
A base station for use with other such base stations in a cellular digital mobile communication network utilising time division multiplex radio communication links with a mobile station, the base station comprising: receiving means for receiving an up-link radio signal directed from said mobile station to a different said base station to measure a reception time instant of reception of said up-link radio signal, and adjusting means for adjusting, based on said reception time instant, a transmission time instant of transmission of the base station down-link signal to said mobile station.
Claim 10
Dependent Claim
27 words
A cellular digital mobile communication network comprising a synchronization system as claimed in any of Claims 1 to 8 and/or base stations as claimed in Claim 9.
References Cited (Backward Citations)
No citation records indexed.
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