480 likes | 639 Views
Mobile Communications. Introduction to Mobile Systems Radio coverage prediction Cellular radio design principles 2 Generation Sytems (GSM) 3 Generation Sytems (UMTS). Paging Systems. The world of paging ... 1980 tone&voice is king paging systems are analog
E N D
Mobile Communications Introduction to Mobile Systems Radio coverage prediction Cellular radio design principles 2 Generation Sytems (GSM) 3 Generation Sytems (UMTS)
Paging Systems • The world of paging ... 1980 tone&voice is king paging systems are analog tone pagers sell for 200$, tariffs are 20$/month
Paging Systems • The world of paging ... 1993 tone alert low information content over 1000000 pagers per channels requires an intermediary numeric display digits (phone numbers, codes) memory input by tone dialing or intermediary 50000 to 300000 per channels
Paging Systems • The world of paging ... 1993 tone and voice high information content approximately 1000 per channel alpha message display high information content memory requires alpha keyboard or intermediary 10000 to 100000 per channel pairs well with computerized systems and information services
Top 10 paging countries • US • Japan • China • Taiwan • Korea • Canada • Hong Kong • U.K. • Australia • Singapore
Subscriber paging bands • Frequency ranges Comments 930-931 MHz Good building penetration, high volume 450-512 MHz Good building penetration, medium volume 280 MHz Good propagation, largely limited to Japan 136-174 MHz Good propagation, high volume 88-108 MHz(FM Subcarrier) Low cost implementation, limited coverage, very low volume 68-88 MHz Older systems only 41-45 MHz Poor building penetration 33-37 MHz Poor building penetration
The present wireless systems (1-2. Gen) voice communications Spectrum allocation, spectrum resource management, power controll • 3. Generation systems data, multimedia applications, internet applications Not only Spectrum allocation, spectrum resource management, power controll, dynamic channel allocation, transmit diversity
Table 1.1: Chronological development of mobile radio systems
Introduction to Mobile SystemsMobile Radio Systems Around the World Table 1. Major Mobile Radio Standards in North America
Introduction to Mobile SystemsMobile Radio Systems Around the World Table 2. Major Mobile Radio Standards in Europe
IS-95 is a standard for CDMA (Code Division Multiple Access) Digital Cellular.
High data rates • high data rate applications • different and varying data rates (presently constant) • limiting factor is the radio wave attenuation • with the bandwith linearly increasing the power desired → high data rate applications only in limited area • increasing number of BS → resource management complexity increasing
QoS types • picocell office environment – high peak/average capacity needed • video users – delay time limit needed • e-mail traffic – not sensitive to the time delaying • solution instead of the present TDMA/FDMA multiplexing – dinamic channel allocation (statistic multiplexing)
Circuit switching – packet swithing • packet switching – better usage of the resources for data traffic
Asymmmetric traffic • Now – voice and symmetric full duplex connection : data rates and QoS parameters are the same for the two directions • 3. Generation systems – data traffic mainly IP-based applications – downlink load much greater (in average 10/1 or bigger ration)