PCS 1900 is the American National Standards Institute (ANSI) radio standard for 1900-MHz Personal Communication Service (PCS) in the United States. Also known as GSM 1900, it is compatible with the Global System for Mobile (GSM) communications, an international standard adopted by 404 networks supporting 538 million subscribers in 171 countries as of mid- 2001.
Network operators aligned to the GSM standard have 35 percent of the world’s wireless market. PCS 1900 can be implemented with either Time Division Multiple Access (TDMA) or Code Division Multiple Access (CDMA) technology. TDMA-based technology enjoys an initial cost advantage over rival technology CDMAequipment because suppliers making TDMAinfrastructure equipment and handsets have already reached economies of scale.
In contrast, CDMAequipment is still in its first generation and therefore is generally more expensive. The CDMA(IS-95) standard has been chosen by about half of all the PCS licensees in the United States, giving it the lead in the total number of potential subscribers. However, the first operational PCS networks have been using PCS 1900 as their standard mainly because of the maturity of the GSM-based technology.
Although similar in appearance to analog cellular service, PCS 1900 is based on digital technology. As such, PCS 1900 provides better voice quality, broader coverage, and a richer feature set. In addition to improved voice quality, fax and data transmissions are more reliable. Laptop computer users can connect to the handset with a Personal Computer Memory Card International Association (PCMCIA) card and send fax and data transmissions at higher speeds with less chance of error.
The PCS 1900 system architecture consists of the following major components:
- Switching system Controls call processing and subscriberrelated functions.
- Base station Performs radio-related functions.
- Mobile station The end-user device that supports voice and data communications as well as short message services.
- Operation and support system (OSS) Supports the operation and maintenance activities of the network.
The switching system for PCS 1900 service contains the following functional elements:
- Mobile Switching Center (MSC) Performs the telephony switching functions for the network. It controls calls to and from other telephone and data communications networks such as Public Switched Telephone Networks (PSTN), Integrated Services Digital Networks (ISDN), Public Land Mobile Radio Services (PLMRS) networks, Public Data Networks (PDN), and various private networks.
- Visitor Location Register (VLR) Adatabase that contains all temporary subscriber information needed by the MSC to serve visiting subscribers.
- Home Location Register (HLR) Adatabase for storing and managing subscriptions. It contains all permanent subscriber information, including the subscriber’s service profile, location information, and activity status.
- Authentication Center (AC) Provides authentication and encryption parameters that verify the user’s identity and ensure the confidentiality of each call. This functionality protects network operators from common types of fraud found in the cellular industry today.
- Message Center (MC) Supports numerous types of messaging services, for example, voice mail, facsimile, and e-mail.
Advanced Services and Features
Like GSM, PCS 1900’s digital orientation makes possible several advanced services and features that are not efficiently and economically supported in analog cellular networks. Among them are:
- Short Message Service - Enables alphanumeric messages up to 160 characters to be sent to and from PCS 1900–compatible handsets. Short Message Service applications include two-way point-to-point messaging, confirmed message delivery, cell-based messaging, and voice-mail alert. These messaging and paging capabilities create a broad array of potential new revenue-generating opportunities for carriers.
- Voice Mail - The PCS 1900 network provides one central voice-mail box for both wired and wireless service. In addition, the voice-mail alert feature ensures that subscribers do not miss important messages.
- Personal Call Management - Offers subscribers a single telephone number for all their physical telecommunication devices. For example, a single number can be assigned for home and mobile use or office and mobile use. This allows subscribers to receive all calls regardless of their physical location.
- Data Applications - Wireless data applications that can be supported by PCS 1900 networks include Internet access, electronic commerce, and fax transmission.
The PCS 1900 standard supports the smart card, which provides similar features as GSM’s Subscriber Identity Module (SIM). The size of a credit card, smart cards contain embedded computer chips with user-profile information.
By removing the smart card from one PCS 1900 phone and inserting it into another PCS 1900 phone, the user is able to receive calls at that phone, make calls from that phone, or receive other subscribed services such as wireless Internet access. The handsets cannot be used to place calls (except 911 emergency calls) until the subscriber inserts the smart card and enters a personal identification number (PIN).
The profile information stored in the smart card also enables international roaming. When traveling in the United States, international GSM customers will be able to rent handsets, insert their SIM, and access their services as if they are back home. By the same token, when U.S. subscribers travel internationally to cities with compatible networks and mutual roaming agreements, they only need to take their smart card with them to access the services they subscribed to back home via the local GSM network.
Like SIMs, smart cards also provide storage for features such as frequently called numbers and short messages. Smart cards also include the AT command-set extensions, which integrate computing applications with cellular data communications. In the future, smart cards and PCS 1900 technology also will link subscribers to applications in electronic commerce, banking, and health care.
PCS 1900 is a frequency-adapted version of GSM that operates at 1800 MHz in Europe and elsewhere. While GSM looks to be a perennial third in North America digital markets, this is mainly because the technology has not been adopted for use in cellular 800-MHz frequencies. Otherwise, PCS 1900 and GSM are similar in all other respects, including the network architecture and types of services supported.
An advantage U.S. carriers have in supporting the PCS 1900 standard is that it is interoperable with the worldwide GSM standard, which means that users can roam globally. GSM phones are available in either dual-band (900/1900 MHz) or triband (900/1800/1900 MHz) models, enabling their use in countries with different frequency bands for GSM services.