Distributed packetized switching cellular radio telephone communication system with handoff

• US 5,384,826 A
• Filed: 07/28/1993
• Issued: 01/24/1995
• Est. Priority Date: 10/01/1990
• Status: Expired due to Term

• Current Assignee: AT&T, Inc.
• Original Assignee: AT&T, Inc.
• Inventors: Amitay, Noach
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US08/098,759
• Time in Patent Office: 545 Days
• Field of Search: 370/85.1, 370/94.1, 370/110.1, 375/1, 379/56, 379/58, 379/59, 379/60, 455/31.1, 455/33.1, 455/56.1
• US Class Current: 455/436
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 8/06 Registration at serving network Location Register, VLR or user mobility server
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks
• CPC Class Codes: H04W 92/20 between access points

Abstract

A cellular switching system and architecture is described in which the switching associated with a call originated within one cell but now serviced within another cell is distributed among base stations which are interconnected with each other through a local area network or a packet switch. The routing procedure associated with the point of origin for a given call is stored in the memory of a switch of public switched telephone network. As an active subscriber crosses a cell boundary, the switch routes all packets of information for the given call to the originating base station for the duration of the call. Importantly, each base station then forwards each packet to the subscriber'"'"'s current base station via the local area network or a packet switch. In this manner, the inventive architecture is unaffected by the increased crossing between cell boundaries since the switching associated with those calls not within the range of the initial base station is handled in a distributed manner by each base station via the local area network or a packet switch.

Claims

1. A packetized cellular communications system, comprising:

a plurality of base stations, each respective base station being directly connected to a public switched telephone network by means of at least one transmission line defining a plurality of communications channels between the respective base station and the public switched telephone network and;

a means independent of the public switched telephone network for interconnecting the plurality of base stations;

each respective base station, comprising;

a means for receiving communications packets from a cellular subscriber in the respective base station, the packets comprising a present base station identification representing a current location of a cellular subscriber, an original base station identification representing where a call to which the communications packets are associated was initiated, and a line assignment representing one of the communications channels between a base station and the public switched telephone network; and

a means for selectively directing the communications packets received by the respective base station to one of;

(a) the public switched telephone network by means of one of the communications channels between the respective base station and the public switched telephone network; and

(b) the public switched telephone network through the interconnecting means, an original base station, different from the respective base station, where a call associated with the communications packets was initiated, and one of the communications channels between the original base station and the public switched telephone network,

in response to the present base station identification, the original base station identification, and the line assignment.

2. The cellular communications system of claim 1, in which each respective base station further comprises:

a means for selectively directing communications packets associated with signals received from the public switched telephone network to one of;

(a) a cellular subscriber connected to the respective base station by means of a wireless communications channel between the cellular subscriber and the respective base station when a call associated with the communications packets from the public switched telephone network was initiated at the respective base station and has not been handed-off from the respective base station; and

(b) a cellular subscriber connected by means of a wireless communications channel to another base station after at least one hand-off from the respective base station by way of the interconnecting means.