Economical synchronization system for asynchronous transfer mode mobile communication network without dependence on external system

Claim 1

An asynchronous transfer mode network comprising: a plurality of low-level stations communicable with at least one mobile station in a boundary zone between service cells of said plurality of low-level stations; a high-level station communicable with said plurality of low-level stations through respective asynchronous transfer mode channels; and a synchronization system including a plurality of clocks each respectively associated with a corresponding one of said high-level station and said low-level stations, and each clock independently indicating a current time, a message transmitting unit associated with said high-level station and concurrently transmitting a control message from said high-level station to said plurality of low-level stations through said asynchronous transfer mode channels, a plurality of message relaying units each respectively associated with a corresponding one of said plurality of low-level stations, for replaying said control message from one of said plurality of low-level stations of said at least one mobile station, each message relaying unit respectively receiving a first response message respectively supplied from said at least one mobile station to said plurality of low-level stations and respectively transmitting a second response message from said plurality of low-level stations through said asynchronous transfer mode channels to said high-level station, for each mobile station of said at least one mobile station, a first message generator associated with the corresponding mobile station and respectively transmitting said first response messages to said plurality of message relaying units after said at least one mobile station receives said control message, a plurality of second message generators each respectively connected to a corresponding one of said plurality of message relaying units and respectively producing said second response message, each second response message representative of the current time indicated by the clock associated with the corresponding one of said plurality of low-level stations and a first message exchange period between said corresponding one of said plurality of low-level stations and said at least one mobile station, and a timing regulator connected to said message transmitting unit and determining a difference between transmitting time lags along said asynchronous transfer mode channels on the basis of said second response messages and a plurality of second message exchange periods between said high-level station and said at least one mobile station through said low-level stations for supplying a piece of control information representative of said difference between said transmitting time lags to said plurality of low-level stations.

Claim 13

A method of synchronizing base stations in an ATM mobile communication network when a mobile station is in a boundary condition between adjacent base stations, comprising: sending a first control signal from a high-level station to a plurality of base stations; relaying the first control signal to the mobile station from one of the plurality of base stations; after receiving the control signal, transmitting a first response message from the mobile station to the plurality of base stations; at each base station, sending a second response message to the high-level station after receiving the response message; at the high-level station, calculating a time lag of each base station based on the second response messages received from each of the base stations and the corresponding arrival times thereof; and transmitting, from the high-level station, a second control message to the plurality of base stations to synchronize the base stations.

Claim 14

A method of synchronizing base stations in an ATM mobile communication network when a mobile station is in a boundary condition between adjacent base stations, comprising: sending a first control signal from a high-level station to a plurality of base stations; relaying the first control signal to the mobile station from one of the plurality of base stations; after receiving the control signal, transmitting a first response message from the mobile station to the plurality of base stations; at each base station, sending a second response message to the high-level station after receiving the response message; at the high-level station, calculating a time lag of each base station based on the second response messages received from each of the base stations and the corresponding arrival times thereof; and transmitting, from the high-level station, a second control message to the plurality of base stations to synchronize the base stations.