Điện thoại di động vô tuyến điện - Tuyên truyền Channel P9 pptx

... UHF bands, for example, television, domestic radio, Citizens' Band radio, marine radio, aeromobile radio (including instrument landing systems) and military radio. Several of these services have a ... size. For two-way mobile radio, particularly in urban areas, it is seldom that the mobile antenna has a direct line-of-sight path to the base station. Radio waves will penetrate into buildi...

Ngày tải lên: 01/07/2014, 17:20

... Ltd Print ISBN 0-4 7 1-9 8857-X Online ISBN 0-4 7 0-8 415 2-4 rough the specular re¯ection assumption is no longer realistic since a rough surface presents many facets to the incident wave. A di use re¯ection ...  power density at a distance d in the direction of maximum radiation P T =4pd 2 where P T is the power supplied to the antenna. The Mobile Radio Propagation Channel. Se...

Ngày tải lên: 01/07/2014, 17:20

... (250 to 400 N-units) . Eective Earth radius . Ground constants . Climate In addition it is necessary to provide a number of path-speci®c factors: . Eective antenna heights . Horizon distances ... Figure 3.12, the radius of a hill crest may be estimated as r  2D s d st d sr ad 2 st  d 2 sr  3:25 3.5 MULTIPLE KNIFE-EDGE DIFFRACTION The extension of single knife-edge di raction theory ....

Ngày tải lên: 01/07/2014, 17:20

... standard deviation of the prediction error in the range 7±9 dB with the three- dimensional models among the best. Over-rooftop and around-building di raction Propagation in Built-up Areas 109 Table 4.8 ... buildings. Propagation in Built-up Areas 87 Figure 4.11 Deviation from median ®eld strength curve due to buildings surrounding the mobile terminal. 52. Reudink D.O. (1972) Comparison of ra...

Ngày tải lên: 01/07/2014, 17:20

... fading. The Mobile Radio Propagation Channel. Second Edition. J. D. Parsons Copyright & 2000 John Wiley & Sons Ltd Print ISBN 0-4 7 1-9 8857-X Online ISBN 0-4 7 0-8 415 2-4 The signi®cance of ... radio waves arrive from di erent directions with di erent time delays. They combine vectorially at the receiver antenna to give a resultant signal which can be large or small de...

Ngày tải lên: 01/07/2014, 17:20

... Rayleigh model. The Mobile Radio Propagation Channel. Second Edition. J. D. Parsons Copyright & 2000 John Wiley & Sons Ltd Print ISBN 0-4 7 1-9 8857-X Online ISBN 0-4 7 0-8 415 2-4 42. Bultitude R.J.C., ... time-delay pro®le within a large six-storey building (after Devasirvatham). Figure 7.4 Cumulative distribution of time-delay spread within two oce buildings. Chapter 7...

Ngày tải lên: 01/07/2014, 17:20

... mobile use [20], they have not yet been used extensively in studies of mobile radio channels. 8.8 WIDEBAND SOUNDING TECHNIQUES Channel sounding using a number of narrowband measurements (simultaneously ... mobile propagation channel, the received signal represents the convolution of the sounding pulse with the channel impulse response. In order to observe the time-varying behaviour of th...

Ngày tải lên: 01/07/2014, 17:20

... lines and The Mobile Radio Propagation Channel. Second Edition. J. D. Parsons Copyright & 2000 John Wiley & Sons Ltd Print ISBN 0-4 7 1-9 8857-X Online ISBN 0-4 7 0-8 415 2-4 distribution of the ... the 270 The Mobile Radio Propagation Channel Figure 9.5 A typical amplitude probability distribution (APD) curve: (- - - -) receiver noise. 292 The Mobile Radio Pro...

Ngày tải lên: 01/07/2014, 17:20

... this: output SNR has been computed for single-path (equivalent to SC), all-path EGC and all-path MRC, from available channel- sounding information [31]. All-path MRC produced an increase, at the 50% ... between 4-path and all-path receivers is negligible. In IS-95 ± a system designed for wide area coverage and using a much smaller band- width than the channel sounder mentioned above ± 3-p...

Ngày tải lên: 01/07/2014, 17:20

... and the di raction loss can be estimated. The distance between points and the propagation mode (whether line-of- sight, partial line-of-sight or non-line-of-sight) can be determined and displayed 374 ... brie¯y here. The Mobile Radio Propagation Channel. Second Edition. J. D. Parsons Copyright & 2000 John Wiley & Sons Ltd Print ISBN 0-4 7 1-9 8857-X Online ISBN 0-4 7 0-8 415...

Ngày tải lên: 01/07/2014, 17:20