COVERAGE VERSUS CAPACITY Paraphrasing the late Tip O Neill: All coverage is local. With 12 14-in. full wavelengths it is quite possible to encounter an ARDIS, BSWD, CDPD, or circuit switched cellular dead spot simply by walking to another position in a room. This annoying fact does not mean that all carriers operating near the same frequency band offer essentially the same coverage choices. Design trade-offs are made between area coverage and its close cousin, building penetration, versus subscriber capacity. . | The Wireless Data Haadbaak Fourth Edition. James F. DeRose Copyright 1999 John Wiley Sons Inc. ISBNs 0-471-31651-2 Hardback 0-471-22458-8 Electronic III BUSINESS 102 OTHER THINGS ARE IMPORTANT TOO The Wireless Data Haadbaak Fourth Edition. James F. DeRose Copyright 1999 John Wiley Sons Inc. ISBNs 0-471-31651-2 Hardback 0-471-22458-8 Electronic 12 COVERAGE VERSUS CAPACITY INTRODUCTION Paraphrasing the late Tip O Neill All coverage is local. With 12-14-in. full wavelengths it is quite possible to encounter an ARDIS BSWD CDPD or circuit switched cellular dead spot simply by walking to another position in a room. This annoying fact does not mean that all carriers operating near the same frequency band offer essentially the same coverage choices. Design trade-offs are made between area coverage and its close cousin building penetration versus subscriber capacity. These trade-offs flow from fundamental decisions on channels allocated for data versus control channel reuse philosophy base station quantity and location transmit power levels FM capture exploitation bit rates and message redundancy to name just a few. Each of these decisions can cloud the certainty of coverage comparisons. ARDIS configures minimal infrastructure for maximum in-building penetration at the cost of subscriber capacity. For roughly equivalent geography BSWD s technical choices predispose it toward maximum subscriber potential at the cost of some penetration. CDPD is not closely comparable to either ARDIS or BSWD because in a full-blown implementation it would deploy many more base stations each with a dedicated channel thereby achieving both high capacity and good penetration. But carriers are hesitant about the cost of a CDPD deployment of that scope. Bell Atlantic Mobile has stated1 CDPD will be offered in markets where it is expected to be commercially viable although equipment will not be installed at all cell sites in those markets. This uncertainty does not mean that coverage is simply
