Large area characterisation of urban UHF multipath propagation and its relevance to the performance bounds of mobile radio systems

Medium- and Large-Scale Characterization of UMTS-Allocated Frequency Division Duplex Channels

“…It is, however, necessary to consider the distance traveled by the mobile in relation to the time delay resolution of the sounder. For example, in the measurements reported by Cox [13] and Bajwa and Parsons [14], an average PDP was obtained over 5-30 and 5 m, respectively, where the corresponding resolutions of the sounders were 30 m. It is therefore appropriate to define the duration (or distance) over which an average delay profile is For the trolley data, the highest detected Doppler shift was on the order of 35 Hz, which is close to the above limit. The maximum Doppler shift experienced in the van measurements was 80 Hz.…”

Channel equalization for the GSM system

“…where gMF(t) is given by (3). The integer L is selected such that 2LT is the true duration of the combined response.…”

“…Delay spreads of the order of 1 to 3 /xs or more have been observed with signals propagated in dense urban areas [2,3]. These figures are a significant fraction of the 3.7-#s symbol time used by GMSK (bit rate of 270 ~ kbps).…”

Digital modems for land mobile radio

“…It is, of course, assumed here that only a single modulated carrier signal is transmitted through the HPA. The transmitted radio signal (electromagnetic radiation) from the transmitter aerial ideally reaches the receiver aerial via a single path (sky wave), although in practice there are often two or more (and sometimes many) different sky waves reaching the receiver, caused by reflections from buildings and hills, and resulting in 'multipath propagation' [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. In the case of the land mobile radio systems considered here, the overall spread of the transmission delays of the various sky waves is most often only a small fraction of the duration T of an individual signal element, and under these conditions 'flat fading' is introduced into the received signal, all frequency components of the signal fading together [17].…”

“…A further cause of fading is the obstruction of the radio signals by buildings and hills, and this is known as 'shadowing'. Although this may lead to sudden deep fades, as when a vehicle passes at speed under a low bridge, the fading rate due to shadowing is typically very much less rapid than that caused by multipath propagation [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].…”