Method of upgrading a cellular network

• US 5,251,249 A
• Filed: 11/26/1990
• Issued: 10/05/1993
• Est. Priority Date: 11/26/1990
• Status: Expired due to Term

• Current Assignee: Rockstar Bidco LP (Rockstar Consortium Inc.)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Allen, Daniel L., La Bauve, Lance M., Meghani, Aziz A.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Bost, Dwayne D.
• Application Number:
  US07/617,547
• Time in Patent Office: 1,044 Days
• Field of Search: 379/59, 379/63, 455/33.1, 455/33.2
• US Class Current: 455/448
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource

Abstract

A method of enhancing an existing cellular network is described such that a new system can operate in tandem with an existing cellular network without disrupting service to existing subscribers and without requiring the replacement of existing equipment. In particular, this is achieved by giving control of all dedicated control channels (CCHs) in each cell to a second switch. The second switch thereby is provided with the control of call set-ups, thus providing for more than one category of mobile subscriber. Some subscribers can be serviced by the existing switch and others by the second switch.

Claims

1. A method for providing an overlay cellular network and operating in tandem said overlay cellular network with an existing cellular network to upgrade said existing network'"'"'s capacity and service, said existing network having a plurality of cells with at least a first base station in each cell connected to a mobile telephone switching office (MTSO) connected to a public switched telephone network (PSTN), said MTSO having paging/access control channels, said MTSO servicing a first category of subscribers having basic cellular service, said method comprising the steps of:

a) providing a second switching office (SSO) for servicing a second category of subscribers having premium cellular service, said SSO having paging/access control channels;

b) coupling in and out trunks between said PSTN and said SSO;

c) coupling inter-office trunks from said SSO to said MTSO and from said MTSO to said SSO;

d) decoupling in and out trunks between said MTSO and said PSTN;

e) providing a second base station in each cell, said second base station being associated with said SSO;

f) decoupling all dedicated paging/access control channels for each cell associated with said MTSO;

g) assigning for each cell associated with said SSO a paging/control channel such that an incoming or outgoing call of a mobile is initiated through said SSO paging/access control channel;

h) initiating incoming and outgoing calls to and from a mobile through said SSO on one of said paging/control channels assigned to said SSO;

i) setting up by said SSO said incoming and outgoing calls to and from said mobile on a voice channel assigned to said SSO;

j) servicing by said SSO calls directed to and from said second category of subscribers;

k) handing off by said SSO to said MTSO for service calls directed to and from said first category of subscribers from a voice channel assigned to said SSO to a voice channel assigned to said MTSO via said inter-office trunks; and

l) servicing by said MTSO calls handed off by said SSO.

2. A method as in claim 1, wherein:

a) said step k) is implemented using an IS-41 intersystem handoff.

3. A method for providing an overlay cellular network and operating in tandem said overlay cellular network with an existing cellular network to upgrade said existing network'"'"'s capacity and service, said existing network having a plurality of cells with at least a first base station in each cell connected to a mobile telephone switching office (MTSO) connected to a public switched telephone network (PSTN), said MTSO having paging/access control channels, said MTSO servicing a first category of subscribers having basic cellular service, said method comprising the steps of:

a) providing a second switching office (SSO) for servicing a second category of subscribers having premium cellular service, said SSO having paging/access control channels;

b) coupling in and out trunks between said PSTN and said SSO;

c) coupling inter-office trunks from said SSO to said MTSO and from said MTSO to said SSO;

d) decoupling incoming trunks from said PSTN to said MTSO such that all incoming calls from said PSTN are directed to said SSO;

e) providing a second base station in each cell, said second base station being associated with said SSO;

f) providing a modified paging/access control channel for each cell associated with said MTSO such that only the access channel is accessible to a mobile;

g) assigning in each cell associated with said SSO a paging/control channel such that an incoming or outgoing call to and from a first category subscriber is intercepted by said SSO and transferred for service to said MTSO and an incoming or outgoing call to and from a second category subscriber is set up and serviced by said SSO;

h) identifying by said SSO a call from said PSTN as being directed to a subscriber in said first category;

i) capturing said call;

j) sending a paging signal to the called subscriber on a paging/access control channel assigned to said SSO;

k) simultaneously forwarding the captured incoming call to said MTSO along said inter-office trunks;

l) receiving by said SSO a paging response signal from the called subscriber on said paging/access control channel associated with said SSO;

m) sending a page response retry message to the called subscriber to retry a page response on said modified paging/access control channel assigned to said MTSO;

n) receiving by MTSO said captured incoming call from said SSO through said interoffice trunks;

o) sending by said MTSO a paging signal to the called subscriber on said modified paging/access control channel;

p) receiving by said MTSO the retried page response from the called subscriber on said modified paging/access control channel; and

q) servicing the call from said PSTN on a voice channel assigned to said MTSO.

4. A method as in claim 3, wherein:

a) said step f) is implemented by provisioning said paging/access control channels associated with said MTSO such that they operate in frequencies outside of their originally dedicated frequencies.