Personal communication network hand over

• US 5,627,831 A
• Filed: 07/31/1995
• Issued: 05/06/1997
• Est. Priority Date: 07/31/1995
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Azmak, Okan
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): VU, HUY DUY
• Application Number:
  US08/509,699
• Time in Patent Office: 645 Days
• Field of Search: 370/95.1, 370/95.3, 370/13, 370/17, 370/110.1, 370/53, 370/54, 370/58.1, 370/58.2, 370/58.3, 370/60, 455/33.2, 455/49.1, 455/54.1, 455/54.2, 455/56.1, 455/67.1, 455/33.1, 379/60, 379/59, 379/58
• US Class Current: 370/332
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing

Abstract

A technique for handing over between PCS networks that are connected to the ISDN/AIN switches wherein the PCS networks have source-centric hand over and the ISDN/AIN switching infrastructure has target-centric hand over by using AM components.

Claims

1. A method of effecting handover between a first and a second PCS network coupled to an LEC network via a plurality of ISDN/AIN switches;

wherein the first and second PCS networks each have a source-centric handover and the LEC has a target-centric handover, the method comprising;

selecting, at a source access system of the first PCS network, a target access system from a list of target access systems compiled in accordance with the relative signal strength of the source access system and access systems other than the source access system of the first PCS network;

sending from the source access system of the first PCS network to the selected target access system of the second PCS network a first request for handover upon the selection of the target access system;

sending from the selected target access system of the second PCS network a second request for handover, including a specified channel, to the LEC network in response to the first request for handover;

initiating handover procedure in the ISDN/AIN switch of the LEC network associated with the target access system; and

rerouting the PCS connection from the source access system of the first PCS network to the target access system of the second network.

2. The method of claim 1 wherein the step of selecting the target access system from the list of target access systems comprises the substeps of:

measuring at a mobile terminal the strength of signals being received from RPs associated with RPCUs connected to each the plurality of ISDN/AIN switches and compiling a list of those RPs providing stronger signals than the RP of the source access system;

reporting by the source RPCU to the AM of the source access system of a need for handover including a list of the complied target access systems; and

selecting the target access system from the list of target access systems by the AM of the source access system.

3. The method of claim 1 wherein the step of sending from the source access system to the selected target access system the first request for handover, comprises the substep of:

sending a message requesting handover by an AM of the source access system to an AM of the selected target access system.

4. The method of claim 1 wherein the step of sending from the selected target access system a second request for handover, including a specified channel, comprises the substeps of:

requesting, by an AM of the target access system, allocation of a radio channel for handover by an RPCU of the target access system;

allocating the specified radio channel for handover by the RPCU of the target access system; and

sending the request for handover and the specified allocated radio channel by the RPCU of the target access system to the LEC network via said ISDN/AIN switch.

5. The method of claim 1 wherein the step of initiating handover procedure via the second ISDN/AIN switch of the LEC network, comprises the substeps of:

sending a handover request specifying the allocated channel to the first ISDN/AIN switch over an SS7 signalling network;

reporting the channel allocation to the RPCU of the source access system via the ISDN/AIN switch associated with the source access system;

reporting by the RPCU of the source access system the channel allocation to the MS via an RP;

tuning to and sending a signal on the allocated channel by the MS;

receiving, by the RPCU of the target access system, the signal on the channel via the RP;

reporting, by the RPCU of the target access system, to the ISDN/AIN switch serving the target access system that the mobile terminal is tuned to the allocated channel; and

sending a message to the ISDN/AIN switch serving the source access system from the ISDN/AIN switch serving the target access system via the SS7 signalling system indicating that the MS has tuned to the allocated channel.

6. A method of effecting handover between a first PCS network and a second PCS network coupled to an LEC having a target centric handover, via first and second ISDN/AIN switches respectively, wherein the first and the second PCS networks have a source-centric handover, the method comprising:

measuring at an MS the strength of signals being received from RPs other than the source access system and compiling a list of those providing stronger signals than the source access system;

reporting by the source access system RPCU to the AM of the source access system of a need for handover including a list of target access systems;

selecting, by the AM of the source access system, the target access system from the list of target access systems;

sending a first message requesting handover to the AM associated with the selected target access system;

requesting, by the AM of the target access system, allocation of a radio channel for handover by the RPCU of the target access system;

allocating the radio channel for handover by the RPCU of the target access system;

sending a second request for handover including the specified radio channel by the RPCU of the target access system to the LEC network via the second ISDN/AIN switch;

initiating handover procedure by the second ISDN switch, including specifying the allocated channel to the first ISDN switch over the SS7 signalling network;

reporting the channel allocation to the RPCU of the source access system via the first ISDN switch;

reporting by the RPCU of the source access system the channel allocation to the MS via the RP;

tuning to and sending a signal on the allocated channel by the MS;

receiving, by the RPCU of the target access system, the signal on the channel via the RP of the target access system;

reporting, by the RPCU of the target access system, to the second ISDN/AIN switch that the MS is tuned to the allocated channel;

sending a message to the first ISDN/AIN switch serving the source baase station from the second ISDN/AIN switch serving the target base station via the SS7 signalling system indicating that the MS has tuned to the allocated channel; and

rerouting, by the first ISDN/AIN switch serving the source access system, the PSTN connection from the source access system to the target access system.

7. A PCS network coupled to an LEC, wherein the LEC includes a plurality of base stations having switches, each switch having ISDN/AIN portions coupled to a PSTN comprising:

means at a source access system for selecting a target base station from a list of target base stations compiled in accordance with the relative signal strength of a source base station and base stations other than the source base station;

means for sending from the source access system to a selected target access system a first request for handover upon the selection of the target base station;

means for sending from the selected target base station a second request for handover, including a specified channel, to the LEC network via the ISDN/AIN switch of the selected target base station in response to the first request for handover,

the ISDN/AIN switch serving the target base station including means for a handover in the LEC network; and

the ISDN/AIN switch serving the source base station including means for rerouting the PSTN personal communication connection from the source base station to the target base station.

8. The system of claim 7 wherein the means for selecting the target base station from the list of target base stations comprises:

means for measuring at an MS the strength of signals being received from RPs associated with RPCU'"'"'s connected to each of said plurality of ISDN/AIN switches and compiling a list of those providing stronger signals than the RP of the source base station;

means for reporting by the source access sytem RPCU to the AM of the source base station of a need for handover including a list of target base stations; and

means for selecting the target base station from the list of target base stations by the AM of the source access system.

9. The system of claim 7 wherein the means for sending from the source access system to the selected target access system the first request for handover, comprises:

means for requesting handover by an AM of the source access system to an AM of the selected target access system.

10. The system of claim 7 wherein the means for sending from the selected target access system a second request for handover, including a specified channel, comprises:

mean for requesting, by the AM of the target access system, allocation of a radio channel for handover by an RPCU of the target base station;

means for allocating the specified radio channel for handover by the RPCU of the target base station; and

means for sending the request for handover and the specified allocated radio channel by the RPCU of the target access system to the LEC network via the IDSN/AIN switch serving the source base station.

11. The system of claim 7 wherein the means for initiating handover procedure by the ISDN/AIN switch serving the target base station in the LEC network, comprises:

means for sending a handover request specifying the allocated channel to the ISDN/AIN switch serving the source access system over an SS7 signalling network;

means for reporting the channel allocation to the RPCU of the source access system via the ISDN/AIN switch serving the source base station;

means for reporting by the RPCU of the source access system the channel allocation to the MS via an RP;

the MS including means for tuning to and sending a signal on the allocated channel;

means for receiving, by the RPCU of the target access system, the signal on the channel via the RP;

means for reporting, by the RPCU of the target access system, to the ISDN/AIN switch serving the target base station that the MS is tuned to the allocated channel; and

means for sending a message to the ISDN/AIN switch serving the source access system from the ISDN/AIN switch serving the target access system indicating that the MS has tuned to the allocated channel via the SS7 signalling system.

12. A system for effecting handover in a personal communication network coupled to an LEC network, wherein the LEC network includes a plurality of switches, each switch having an ISDN and AIN portions coupled to a PSTN, and wherein the PCS network includes an RPCU connected to each of said plurality of ISDN/AIN switches, a plurality of RPs connected to each said plurality of RPCUs and AM coupled to each said RPCU, and wherein the plurality of AMs are in communication with each other through a signal SS7 transfer member, the ISDN/AIN switches including an ALT for providing target-centric handover between the base stations, the system comprising:

means for measuring at a mobile terminal the strength of signals being received from the RPs associated with the RPCUs other than the source base station RPCU and compiling a list of those RPs providing stronger signals than the source base station RPCU;

means for reporting by the source access system RPCU to the AM of the source access system of a need for handover including a list of target base stations;

means for selecting, by the AM of the source access system, the target base station from the list of target base stations;

means for sending a first message requesting handover to the AM associated with the selected target base station;

means for requesting, by the AM of the target access system, allocation of a radio channel for handover by the RPCU of the target base station;

means for allocating the radio channel for handover by the RPCU of the target access system;

means for sending a second request for handover including the specified radio channel by the RPCU of the target access system to the LEC network via the ISDN/AIN switches;

means for initiating handover procedure by the ISDN switch of the target base station in the LEC network, including specifying the allocated channel to the ISDN switch of the source base station over the SS7 signal transfer member;

means for reporting the channel allocation to the RPCU of the source access system via the ISDN switch of the source base station;

means for reporting by the RPCU of the source access system the channel allocation to the MS via the RP;

means for tuning to and sending a signal on the allocated channel by the MS;

means for receiving, by the RPCU of the target access system, the signal on the channel via the RP;

means for reporting, by the RPCU of the target access system, to the ISDN/AIN switch of the target access system that the MS is tuned to the allocated channel;

means for sending a message to the ISDN/AIN switch of the source access system from the ISDN/AIN switch of the target access system indicating that the MS has tuned to the allocated channel via the SS7 signalling transfer member; and

means for rerouting, by the ISDN/AIN switch of the source access system, the PSTN connection from the source base station to the target base station.