Agenda - 09-03-2002 - 9b - Laserfiche WebLink

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_ 15 and is thus extremely valuable and coveted. The wireless telecommunication industry is limited to a small portion of radio spectrum bandwidth. Cellular, SMR, ESMR, and GSM service occupies portions of the 800 MHz band of the electromagnetic spectrum. PCS encompasses two different services licensed by the FCC,which are delivered over two different frequency bands, as well as certain unlicensed services. The first is Narrowband PCS, to which 3 MHz has been allocated in the 900 MHz band of the electromagnetic spectrum. Narrowband PCS usually includes specialized services such as messaging and advanced paging. The other form of PCS is Broadband,to which a 140 MHz block in the 1850-1990 MHz band of the electromagnetic spectrum has been allocated. CMRS licenses are sold by geographic regions identified as trading and serving areas. Frequencies in the A and B blocks of the PCS band are allocated in Major Trading Areas (MTA); frequencies in bands C,D, E, and F are assigned to Basic Trading Areas(BTA). Similarly, frequencies in the A and B blocks of the cellular bands are assigned to Metropolitan Serving Areas (MSA)and Rural Serving Areas(RSA). Loudoun County lies within the Washington 10 MTA,Washington 9 BTA, and Washington MSA. Loudoun County is not located within a RSA(See Figures 16, 17, 18). There are six (6)commercial mobile radio service providers licensed to provide service in the County. They are:AT&T Wireless, Cingular,Nextel,Sprint PCS,Verizon Wireless, VoiceStream Wireless. As best could be determined,the frequency block,license market area, bandwidth,and frequency band for each provider is presented in Table 5. Coverage Versus Capacity Wireless networks are designed with two objectives in mind. The first is to provide adequate coverage over the target area and the second is to provide the necessary capacity to satisfy the demand calls at any given time within the coverage area. Coverage sites expand service in large areas with difficult terrain and allow users to make and maintain calls as they travel between cells. Due to technological constraints, there is a finite number of calls that a given cell site can handle at any one time. Capacity sites increase the number of call handling capability when the surrounding sites have reached their practical channel limit. In the past, cellular phones have used analog transmission signals. A problem with this technology is that it tends to pickup"noise"sometimes making messages difficult to hear. Most providers have now switched to digital transmissions. Digital wireless facilities have a higher calling capacity than analog cellular sites. However, due to higher frequencies on the electromagnetic spectrum, each PCS cell site will cover a smaller area, and thus will need to be spaced closer together compared with transmissions in the 800 MHz band. In densely populated cities like Washington,D.C.,cell sites tend to be smaller and spaced closer together than in suburban or rural areas due to the fact that there are more people, thus more potential wireless users. As more people demand wireless service,there will be a need to add additional sites to handle the calls. Adding cell sites between existing sites to increase capacity is called"splitting a cell." As the number of cell sites increases,the area of each site offered by a provider is reduced in order to avoid overlapping coverage. As a result, a pattern emerges in which the more populated central segments of cities contain smaller and more numerous cell sites,while the less populated edges of cities,as well as rural areas,have fewer,but larger cell sites. Figure 19 contrasts cell site development within and between urbanized areas.