Method and apparatus for enabling mobile-to-mobile calls in a communication system
First Claim
1. A communication system which reduces loop delay when a first mobile station calls a second mobile station, said first and second mobile stations being served by a same relay station, comprising:
- said relay station for communicating with said first and second mobile stations;
a transponder means located in said relay station for relaying signals received from one mobile station on a first frequency band to another mobile station on a second frequency band; and
control means for controlling the operation of said transponder means using control information.
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Accused Products
Abstract
A communication system is disclosed which reduces loop delay when a first wireless phone calls a second wireless phone wherein the first and second phones are served by the same relay station. The communication system includes a relay station for communicating with the first and second wireless phones. A transponder located in the relay station relays signals received from one mobile station on a first frequency band to another mobile station on a second frequency band. In addition, the transponder sends the received signals to a controller which controls the operation of the transponder using control information.
39 Citations
22 Claims
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1. A communication system which reduces loop delay when a first mobile station calls a second mobile station, said first and second mobile stations being served by a same relay station, comprising:
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said relay station for communicating with said first and second mobile stations; a transponder means located in said relay station for relaying signals received from one mobile station on a first frequency band to another mobile station on a second frequency band; and control means for controlling the operation of said transponder means using control information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for providing encryption of a call between two mobile stations relayed through a satellite in a mobile satellite communication system, comprising the steps of:
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requesting an enciphered connection with a second mobile station; determining whether the second mobile station is reachable only by a satellite relay station; allocating a direct mobile-to-mobile transponder channel in the satellite for the call when the second mobile station is only reachable by a satellite; allocating a first enciphering key to be used by both of the mobile stations; sending identification of said transponder channel and said first enciphering key to the first mobile station; informing the second mobile station of the call, identification of said transponder channel and said first enciphering key; and connecting the call. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. An authentication procedure for verifying the identity of mobile stations which have been granted a direct relay connection, comprising the steps of:
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establishing a key for encrypting signals transmitted by the mobile stations during call setup; periodically monitoring at a mobile switching center and comparing encrypted signals transmitted between the mobile stations to said established key; terminating the connection when the encrypted signals do not correspond to said established key. - View Dependent Claims (20)
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21. An authentication procedure for verifying the identity of mobile stations which have been granted a direct relay connection by a mobile switching center, comprising the steps of:
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establishing a predetermined authentication calculation during call set-up; periodically issuing a SACCH message from said mobile switching center instructing at least one of the mobile stations to perform the predetermined authentication calculation; transmitting a result of said predetermined authentication calculation to said mobile switching center; terminating the connection when the result is invalid. - View Dependent Claims (22)
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Specification