Wireless digital network

A method for providing communication between a plurality of mobile units provided with means for receiving and transmitting signals and a PSTN with at least one central office switch coupled lo a service control point coupled to a wireless integrated services digital network having a plurality of intelligent cellsites, a central site controller and a billing aggregator interconnected through the ISDN, the method comprising the steps of:

• a. receiving, at a first intelligent cellsite, a request for service from one of the mobile units;
• b. requesting, in response to the service request, authorization from the central site controller to provide communication service to the mobile user;
• c. allocating an ISDN bearer channel and radio frequency channel for the use of the mobile unit;
• d. informing the mobile unit of the radio frequency channel;
• and
• e. receiving a terminating number from the mobile unit and causing the first intelligent cellsite to communicate the terminating number;
• and
• f. verifying that the second intelligent cellsite received the correct hand off to the central office switch so that the mobile unit is connected to the terminating number, wherein the verifying step comprises the steps of:
• i. creating a call state record, at the first intelligent cellsite, comprising the calling line identification of the telephone number with which the mobile unit is communicating;
• ii. forwarding the call state record to the second intelligent cellsite;
• and
• iii. comparing, at the second intelligent cellsite, the calling line identification number within the call state record with a calling line identification number provided within a message sent by the central office switch before connecting the call to the second intelligent cellsite.

Apparatus for converting a wireless communications network, having a plurality of base stations each deployed within a cell covering a specific geographic region and capable of radio communication with a mobile unit located within the cell, into a wireless integrated services digital network that interfaces with a PSTN equipped with ISDN and Public Packet Switched Network ("PPSN") capabilities in order to make use of the PSTN switching functionality to route calls generated within the PSTN to the mobile unit or route calls generated by the mobile unit to the PSTN and that can transfer and receive calls to and from a second wireless network, the apparatus comprising:

• a plurality of intelligent cellsites, each capable of interfacing with the base station located within the intelligent cellsite and communicating with one another via data messages transmitted over the ISDN, each intelligent cellsite comprising:
• i. means for communicating with the ISDN network in order to provide at least one signalling and a plurality of communications channels;
• ii. first means for interfacing with the base station to allow information received from the ISDN to be transmitted by the base station to the mobile unit;
• iii. second means for interfacing with the ISDN to allow information received from the base station to be transmitted over the ISDN;
• and
• iv. control means for allocating a radio and ISDN communication channel to allow the mobile unit to communicate with the ISDN network;
• and
• means for storing information relating to the mobile unit, wherein the storing means is interconnected with the ISDN in order to communicate with each intelligent cellsite, a service control point of the PSTN, and with the second network in order to execute the hand off of the mobile unit from a first base station to a second base station, wherein the storing means further comprises means for emulating a mobile switching center in order to execute hand offs with the second network.

A wireless communication network, associated with a second, switched digital network, for using a distributed switching architecture to route communications to and from a plurality of users equipped with radio communication means through the switched digital network, the wireless communications network comprising:

• a) a first and second intelligent cellsite, each comprising a computer, an interface for communicating with a base station capable of radio communication with the users while they are located within a cell covering a preselected geographic area and a digital network interface;
• b) a central site controller comprising (i) a database for containing information associated with the users, (ii) means for sending and receiving packet data through the switched digital network, (iii) means for communicating with a service control point programmed to communicate with the central site controller and capable of controlling a plurality of central office switches for switching communications through the switched digital network and (iv) means for emulating a mobile switching center in order to execute hand offs with a second wireless network;
• c) a processor capable of processing billing information generated by communication with the users;
• and
• d) the switched digital network interconnects the first and second intelligent cellsites, the central site controller and the processor, wherein radio communications from users to a destination within the switched digital network are received at the base stations and pass through the interfaces of the first and second intelligent cellsites into the digital network interface to the central office switches so that the communications are routed to a destination within the switched digital network.

A method of handing off a wireless call, in response to degradation of a signal generated by a user, from a first intelligent cellsite having a base station in radio communication with the user to a second intelligent cellsite, wherein the method comprises the steps of:

• programming the central office switches of a PSTN with the capability of quickly transferring the call between the central office switches;
• determining that a hand off is required;
• selecting the second intelligent cellsite for receiving the hand off;
• transmitting a hand off request from the first intelligent cellsite to the second intelligent cellsite;
• causing the central office switch to connect the call to the second intelligent cellsite and disconnect the first intelligent cellsite;
• and
• verifying that the second intelligent cellsite received the correct hand off, in which the verifying step comprises the steps of:
• a. creating a call state record, at the first intelligent cellsite, comprising the calling line identification of the telephone number with which the mobile unit is communicating;
• b. forwarding the call state record to the second intelligent cellsite;
• and
• c. comparing, at the second intelligent cellsite, the calling line identification number within the call state record with a calling line identification number provided within a message sent by one of the central office switches before connecting the call to the second intelligent cellsite.