In 1994, the FCC allocated the frequency range 1850-1990MHz for mobile phone communication. The goals of this new allocation were to raise money for the U.S. Treasury by auctioning the PCS licenses to mobile operators, to provide more capacity for the (increasingly popular at that time) mobile phone networks, and to promote competition among mobile phone operators by increasing the maximum number of operators per market from 2 (Cellular A and Cellular B) to 8 (Cellular A&B and PCS A-F). This new band is officially called the PCS (Personal Communication Service) band, and is often referred to as 1900MHz. The PCS band is subdivided into six sub-bands, each of which can be used by a different company in each area. The main advantage of running a mobile phone system in the PCS band is that there is more available spectrum there, so the licenses are easier and cheaper to obtain. The introduction of the PCS band also helped relieve some of the congestion that the 800MHz Cellular systems were experiencing, due to some 800MHz subscribers switching to PCS companies, and due to traditional 800MHz cellular operators installing supplemental PCS systems in busy areas. The main disadvantage of PCS systems is that they generally do not have as thorough in-building coverage (and coverage in general) as Cellular (800MHz) systems. There are two causes for this: First, PCS operators have not been in business as long as cellular operators and may not have had enough time to fully build out their networks (build and install base station sites). Additionally, 1900MHz signals have a shorter wavelength than 800MHz signals, which means that they will not travel as far through open air and will not penetrate building materials as well as 800MHz signals do. However, with a properly engineered 1900MHz system (i.e. one with enough base stations placed in good locations), coverage can be as good as or better than 800MHz systems. This PCS coverage catch-up has not occurred yet in many US markets, but most PCS service providers are still actively improving their networks. In some areas, some PCS services can have extremely poor coverage, so buyer beware. However, in other places (usually beginning in larger cities and gradually spreading to smaller cities and rural areas), PCS systems work very well. Some wireless providers in the USA that use the 1900MHz PCS band in at least part of their network include:
It is interesting to note that PCS carriers (and 800MHz carriers, but it matters less in the 800MHz band because coverage there is usually already adequate) who use a CDMA system (IS-95 or any CDMA2000) should, at least in theory, enjoy a small but possibly significant coverage advantage compared to non-CDMA carriers in the same band given the same base station locations. This is because a CDMA phone can receive signals from multiple base stations and combine them into a stronger signal during a conversation. Therefore if a call is placed from an area on the outskirts of coverage of three (for instance) different base stations, a CDMA phone may receive a clearer total signal than a non-CDMA phone due to this combining. (Non-CDMA protocols cannot do this for various technical reasons.) |