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A telecommunications system has a first transmitter unit for transmitting first signals to at least one station; a second transmitter unit for transmitting second signals to at least one station; a receiving unit associated with the first transmitter unit for receiving the second signals; and a sync

A telecommunications system has a first transmitter unit for transmitting first signals to at least one station; a second transmitter unit for transmitting second signals to at least one station; a receiving unit associated with the first transmitter unit for receiving the second signals; and a synchronization unit coupled to the receiving unit for generating a control signal to at least one of the first and second transmitters to increase the synchronization of the first and second signals.

대표청구항 ▼

1. A telecommunications system comprising:a first transmitter unit for transmitting first signals to at least one station; a second transmitter unit for transmitting second signals to at least one station; a first receiving unit associated with the first transmitter unit for receiving the second sig

1. A telecommunications system comprising:a first transmitter unit for transmitting first signals to at least one station; a second transmitter unit for transmitting second signals to at least one station; a first receiving unit associated with the first transmitter unit for receiving the second signals; a second receiving unit associated with the second transmitter for receiving said first signals; and a synchronization unit coupled to both the first and second receiving units; said synchronization unit being arranged to compare the timing of the first signals with the timing of the second signals as received by the respective receiving units and to generate a control signal to at least one of the first and second transmitters to increase the synchronization of the first and second signals. 2. A telecommunications system as claimed in claim 1, wherein at least one of the first and second receiving units is arranged to determine a difference between timing of the first transmitter unit and the second transmitter unit.3. A telecommunications system as claimed in claims 2, wherein at least one of the first and second receiving units is arranged to calculate an average difference between the timing of the first transmitter unit and the second transmitter unit.4. A telecommunications system as claimed in claim 2, wherein at least one of the first and second receiving units is arranged to transmit the difference to said synchronization unit.5. A telecommunication system as claimed in claim 2, wherein said synchronizing unit is arranged to adjust difference in timing determined by each of said receiving units to take into account the relative positions of said transmitter units.6. A telecommunications system as claimed in claim 1 wherein the first and second transmitter units are arranged to be synchronized to within 5 μs.7. A telecommunications system as claimed in claim 1 wherein said synchronization unit is arranged to synchronize said first and second transmitters to a reference clock.8. A telecommunications system as claimed in claim 7, wherein said reference clock is supplied by said synchronization unit.9. A telecommunications system as claimed in claim 7, wherein said reference clock is a clock signal of one of said first and second transmitter units.10. A telecommunications system as claimed in claim 7, wherein said reference clock is the average of clock signals of said first and second transmitter units.11. A telecommunications system as claimed in claim 1, wherein the synchronization unit is arranged to generate said control signal if the timing of said first and second transmitters differ by at least a predetermined amount.12. A telecommunication system as claimed in claim 1, wherein the synchronization unit is arranged to average a difference in the timing of the first and second transmitter units provided by the receiving units associated with the first and second transmitter units respectively.13. A telecommunications system as claimed in claim 1, wherein said system comprises a third transmitter unit and a further receiving unit associated therewith, wherein each of the three receiving units determines the difference of the timing signals between the transmitter unit with which the receiving unit is associated and each of the other two transmitter units.14. A telecommunications system as claimed in claim 13, wherein said synchronization unit is arranged to determine the minimum timing difference between two transmitter units based on a comparison of the timing difference observed by the receiving unit associated with one of the two transmitter units between said transmitter units and the sum of: the difference observed by the receiver unit associated with said one transmitter unit between said one transmitter unit and the third transmitter unit; and the difference observed by the receiver unit associated with the third transmitter unit between the third transmitter unit and the other of the two transmitter units.15. A telecommunications system as claimed in claim 1, wherein at least one of the first and second receiving units is incorporated in the transmitter unit with which the respective receiving unit is associated.16. A telecommunications system as claimed in claim 1 wherein the first and second transmitter units use a time division multiple access method where time is divided into a plurality of slots and said first and second transmitter units transmit signals to different stations in different time slots, said synchronization unit being arranged to synchronize substantially the beginning of time slots of the first and second transmitter units.17. A telecommunications system as claimed in clam 16, wherein the frequency of the first and said second transmitter units changes between time slots.18. A telecommunications system as claimed in claim 16, wherein n time slots are arranged in a frame and each frame has an associated number.19. A telecommunications system as claimed in claim 18, wherein frames having the same frame numbers of said first and second signals are synchronized.20. A telecommunications system as claimed in claim 18, wherein the frames having the same frame numbers of said first and second signals overlap in time but the beginning of said frames do not coincide.21. A telecommunications system as claimed in claim 1, comprising a multiplicity of transmitter units, said multiplicity of transmitter units being divided into a plurality of groups, each group comprising a plurality of transmitter units which are substantially synchronized with the other of the transmitter units in said group and the plurality of groups are not synchronized with respect to each other.22. A telecommunication system as claimed in claim 21, wherein each group comprises three or four transmitter units, each transmitter unit serving a single coverage area.23. A telecommunications system as claimed in claim 21, wherein each group comprises two transmitter units, each transmitter unit serving a plurality of coverage areas.24. A telecommunications system as claimed in claim 1, wherein said system is a wireless cellular telecommunications network.25. A telecommunications network as claimed in claim 24, wherein the wireless cellular network is in accordance with the GSM standard.26. A telecommunications system as claimed in claim 24, wherein at least one of said transmitter units is a base transceiver station.27. A telecommunication network as claimed in claim 24 wherein the synchronization unit is incorporated in a base station.28. A telecommunication network as claimed in claim 1, wherein said synchronization unit is arranged to build a matrix wherein each element of said matrix represents the timing difference between two transmitter units.29. A method for synchronizing a telecommunications system comprising:transmitting first signals to at least one mobile station from a first transmitter unit; transmitting second signals to at least one mobile station from a second transmitter unit; receiving the second signals at said first transmitter unit; receiving the first signals at said second transmitter unit; and comparing at a synchronization unit coupled to both the first and second receiving units, the timing of the first signals with the timing of the second signals as received at the first and second transmitter units and generating a control signal to at least one of the first and second transmitter units to increase the synchronization of the first and second signals. 30. A telecommunications system comprising:a first transmitter unit for transmitting first signals to at least one station where said at least one station is in a first area covered by said first transmitter unit; a second transmitter unit for transmitting second signals to at least one station when said at least one station is in a second area covered by said second transmitter unit; and a timing difference determining unit for determining the difference in timing of said first and second transmitter units and for providing information on said difference to at least one station, said information being used by said station when said station moves between said first and second areas, said timing difference unit being separate from said first and second transmitter units. 31. A station for use in a telecommunications network comprising:a first transmitter unit for transmitting first signals to at least one terminal; and a receiving unit for receiving second signals from a second transmitter unit which is arranged to transmit second signals to at least one terminal, said receiving unit arranged to determine a difference in the timing between said first and second transmitter units, wherein the station is arranged to send the difference in the timing to a separate timing control unit and to receive from the separate timing control unit a control signal for reducing the difference in timing between said first and second transmitter units. 32. A telecommunications system comprising:a first transmitter unit for transmitting first signals to at least one station; a second transmitter unit for transmitting second signals to at least one station; a receiving unit for comparing the time of said first and second signals; and a synchronization unit coupled to the receiving unit for generating a control signal to at least one of the first and second transmitters to increase the synchronization of the first and second signals, said synchronization unit being separate from said receiver unit. 33. A telecommunications system comprising:a first transmitter unit for transmitting first signals to at least one station; a second transmitter unit for transmitting second signals to at least one station; a first receiving unit associated with the first transmitter unit for receiving the second signals; a second receiving unit associated with the second transmitter unit for receiving said first signals; a third transmitter unit; a third receiving unit associated with the third transmitter unit; and a synchronization unit coupled to the first, second and third receiving units for generating a control signal to at least one of the first, second and third transmitters to increase the synchronization of the first and second signals, wherein each of the first, second and third receiving units determines a difference of the timing signals between the transmitter unit with which the receiving unit is associated and each of the other two transmitter units, and wherein said synchronization unit is arranged to determine a minimum timing difference between two transmitter units based on a comparison of the timing difference observed by the receiver unit associated with one of the two transmitter units between said transmitter units and the sum of: (i) the difference observed by the receiver unit associated with said one transmitter unit between said one transmitter unit and the third transmitter unit; and (ii) the difference observed by the receiver unit associated with the third transmitter unit between the third transmitter unit and the other of the two transmitter units. 34. A telecommunication system comprising:a multiplicity of transmitter units divided into a plurality of groups, each group comprising a plurality of transmitter units which are substantially synchronized with one another and the plurality of groups are not synchronized with respect to each other, wherein at least one group comprises; a first transmitter unit for transmitting first signals to at least one station; a second transmitter unit for transmitting second signals to at least one station; a receiving unit associated with the first transmitter unit for receiving the second signals; a synchronization unit coupled to the receiving unit for generating a control signal to at least one of the first and second transmitters to increase the synchronization of the first and second signals. 35. A telecommunications system as claimed in claim 34, wherein each group comprises three or four transmitter units, each transmitter unit serving a single coverage area.36. A telecommunications system as claimed in claim 34, wherein each group comprises two transmitter units, each transmitter unit serving a plurality of coverage areas.