Motorola Corporation

Brian J Wesselman

Dale Robert Buchholz

William K Doss

Michael P Nolan

Alan D Muehlfeld

John E Shaver

Frederick W Vook

Hungkun J Chang

Mai T Nguyen

Charles D Macenski

A method for a synchronizing user devices (12) performing handoffs includes providing a set of location synchronizing frequencies and data frequencies selected from a hopping set used by network access points (14). Each AP transmits synchronizing data (36) at the synchronizing frequencies during a portion of a short dwell (32), the short dwells (32) being interleaved between long dwells (30). When a user device (12) attempt a handoff, it tunes to at least one of the synchronizing frequencies and receives synchronizing information (36). The user device (12) then selects one AP (14) for link transfer and synchronizes its operation to the hopping set used by the selected AP (14).

Synchronization method in a frequency hopping local area network having

A method for handing off user devices (131-134) between network control processors (110, 120) in a frequency hopping communication system (100) includes establishing a set of synchronization frequencies (A-D) for use by said NCPs (110, 120), informing the plurality of user devices (131-134) of said synchronization frequencies (A-D) and assigning a synchronization frequency (A, B, C or D) to each respective NCP, each NCP transmitting synchronization information at its assigned synchronization frequency (A, B, C or D) during each hopping dwell (1-82). Upon a determination that a user device hand-off is necessary, said user device in question (133) tunes to a synchronization frequency (B) different from the synchronization frequency (A) employed by the currently serving NCP (110) and synchronizes its operation to the NCP (120) transmitting synchronization information on the tuned to synchronization frequency (B).

Method for providing hand-offs in a frequency hopping communication

An RF communication system contains a control module which communicates with a plurality of user modules that are each connected to at least one user device. The system provides a method for packet communications in which traditional destination addressed packets are communicated to the specified destination point or user module while also permitting information intended for a plurality of user modules to be broadcast simultaneously to all user modules using a broadcast protocol. The probability of each UM receiving the broadcast packet is enhanced by the transmission by the control module of each broadcast packet over at least several of its directional antennas and preferably repeated over each antenna a number of times. Packets of data which are longer than a predetermined number of bytes are broken into packet fragments.

Broadcasting of packets in an RF system

A CM (105) receives requests for data transfer from a series of UMs (101-103) and from an EM (104). The requests contain the UM (101-103) or EM (104) address and the size of the data packet to be transferred. The CM (105) processes the requests on a FIFO basis, stores the requests in a queue and schedules either a small data channel (415) or a large data channel (420), depending on the packet size to be transferred, an acknowledgement channel (425) and also the corresponding number of required timeslots. The CM (105) picks the first request off the queue and sends a grant to the particular UM (101-103) or EM (104) which receive the grant and immediately access either the assigned small or large data channels (415, 420) in the required number of timeslots and the acknowledgement channel (425).

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Wood Dale, IL, United States of America

Brian J Wesselman