By Dr. Ernest Simo
4.0 PCN ELEMENTS
A conceptual PCN consists of: User smart cards, user entry devices, base stations each serving a microcell, intelligent switches, network control, operations and management databases. Let's review these network components:
4.1 The User Smart Card
The user accesses the network with a Smart Card which is the size of a typical credit card. The Smart Card is specifically coded with electronic information about the user. Unlike today's telephone sets, PCN terminals will not have a pre-assigned telephone number. Each network user will have one or several personal numbers that are encoded onto the Smart Card.
When the user Smart Card is inserted into a handset or any other PCN interface, the network, through SS-7 will be informed about the user's location, the services and capabilities to which he or she has subscribed. The terminal is now triggered to send and receive information. Without a card, a terminal cannot be used for any transaction.
PCN will enable the calls to be charged to the Smart Card holder rather than the line on which the call is made. This is similar to standard transactions with credit cards where the card's owner, not the transaction location, is billed for the services.
4.2 Handset and Base Station
The personal communicator or handset is a low power, light weight, pocket-size unit which could be conveniently carried anywhere. This handset is designed to perform a variety of functions which include storing incoming calls, diverting calls, and setting up conference calls. It could also allow users to view the name and number of the calling person. This unit could be enhanced with data and possible video communications interface modules.
A typical PCN handset consists of telecommunications electronics coupled to the radio subsystem. In the transmit mode, it processes the call, and transmits a modulated RF carrier to a microcell Base Station. After demodulation the Base Station then transfers the call to the microcell controller or wireless PABX. When the handset is In the receive mode, the reverse functions are performed
In an attempt not to compromise user convenience with a host of handsets, Smart, Multimode units will be designed. They'll operate as wireless phones in the Home, as an extension of a PBX or Centrex system in the office, and as a cellular phone in an outdoor environment. That is when the user is mobile on foot, in a car, boat or plane.
Like the handset, the Base Station consists of telecommunications electronics coupled to the RF subsystem and a microcell controller. The controller manages the base station operations, coordinates call hand-offs between microcells and provides the network switches with the appropriate call routing information.
4.3 Switching subsystem and Databases
The PCN intelligent network architecture will be anchored on the Signalling System #7 (SS-7). SS-7 allows a switch operated by a service provider to query a database for information on how a call should be processed and handled. It also permits transmission of information through the network on an end-to-end basis. SS-7 supports features, such as selective call ringing and rejection, virtual private networks, wide-area Centrex and ISDN.
PERSONAL COMMUNCATIONS NETWORKS: AN INTRODUCTION
By Dr. Ernest Simo
© 1999 DR. ERNEST SIMO - SPACE2000