 Personal Communication System  PCS (personal communications service) is a wireless phone service similar to cellular telephone.  It's sometimes referred to as digital cellular.  Technologies used for PCS Time Division Multiple Access (TDMA),TDMA Code Division Multiple Access (CDMA),CDMA Global System for Mobile (GSM) communication. GSM  The goals of PCS are to provide a mobile user with voice, data, and multimedia at any place, at any time, and in any format.

 PCS technologies have grown rapidly in the telecommunications industry.  Two of the most popular are Cellular Telephony Cordless and low tier PCS technology  The basic architecture consist of two parts Radio Network Wireline Transport Network

 PCS users carry mobile stations(MSs) to communicate with the base station in a PCS network.  MS is also referred to as handset,mobile phone,subscriber unit or portable.  The term subscriber unit is used when we describe wireless local loop.  The term portable is used when we describe the low tier system such as PACS.  The term mobile station is used when we describe the GSM system.

 The radio coverage of a base station or a sector in the base station is called a cell.  For systems such as GSM and PACS, The base station system is partitioned into a controller and radio transmitters/receivers.  Controller: (Base station controller in GSM and radio port control unit in PACS)  Radio transmitters/receivers: (base transiever stations in GSM and radio ports in PACS)  The base stations usually reach the wireline transport network via land links or dedicated microwave links.

 The mobile switching center (MSC) connected to the base station is a special switch.  The MSC is connected to the PSTN to provide services between the PCS users and wireline users.  MSC also communicates with mobility databases to track the locations of mobile stations.