Method and apparatus for synchronizing timing among radio ports

Details Method and apparatus for synchronizing timing among radio ports Method and apparatus for synchronizing timing among radio ports

1993-07-30

1994-11-08

Hsu, Alpus H.

Multiplex communications

Wide area network

Packet switching

370108, 375107, 379 58, 455 541, 455 561, 455 673, 455 676, H04B 726, H04B 7212, H04J 306

Patent

active

053633750

ABSTRACT:
In a TDM/TDMA digital radio communications system a few selected ports are connected to a fixed common timing reference and designated as master ports. Each master port is assigned a hierarchical value of zero. Every other port is initialized a high hierarchical value before performing an autonomous iterative procedure to synchronize timing to its nearest master port. By demodulating downlink signals transmitted from other ports when its own transmitter is turned off, a receiving port selects only a fixed number of ports providing the best signal quality with respect to which to adjust its timing. The relative timings and the hierarchical values of the transmitting ports are compared with those of the receiving port. If the hierarchical value of the receiving port, H.sub.R, is greater than or equal to the lowest hierarchical value, H.sub.L, of the transmitting ports, it adjusts its timing based on the timing differences with respect to the set of ports having a hierarchical value of H.sub.L and which have the highest signal quality. Further, H.sub.R is set to H.sub.L +1 if H.sub.R is greater than H.sub.L. The master timing propagates rapidly in a hierarchical way, which results in time synchronization of the entire system without timing drift.

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