Nhiều giao thức truy cập đối với truyền thông di động P7

... Poisson distributed, this distribution will be used in the following. If we ignore the fact that a continuous distribution is being compared with a discrete distribution, when K  0, the Poisson distribution ... steady-state distribution (Equation (7.2)) is a binomial distribution with parame- ters M and α v . The Poisson distribution with mean V = M · α v is a good approximation of the binom...

Ngày tải lên: 07/11/2013, 21:15

... usually distinguished. These are the pathloss, slow fading or shadowing, and fast fading or multi- path fading. The pathloss describes the average signal attenuation as a function of the distance ... be accessed by contending users and carry traffic of users holding a reservation. However, it is also relevant for UTRA FDD, where users holding a reservation (e.g. on dedicated channels) are ......

Ngày tải lên: 20/10/2013, 18:15

... technologies and digital broadcast technologies such as Digital Audio Broadcast (DAB) and Digital Video Broadcast (DVB) as a main 4G ingredient. This would indeed imply a fundamental paradigm shift ... standardisation of the UTRA FDD and TDD modes from ETSI (with UTRA now standing for universal terrestrial radio access rather than UMTS terrestrial radio access). Apart from ETSI and Japanese b...

Ngày tải lên: 20/10/2013, 18:15

... layer, as indicated in Figure 3.1. In a mobile communications system, however, the transmission medium is the error prone radio channel, a medium subject to shadowing and fast fading. Designing ... for instance provide dedicated C-slots, as discussed in the following subsection. 3.6.4 Proposed Modifications and Extensions to PRMA In the recent past, several extensions and modifications to PRMA...

Ngày tải lên: 24/10/2013, 16:15

... symbols, each symbol corresponding to a two-way transmission distance of approximately 1100 m. The maximum two-way transmission distance is 70 km, hence the maximum cell radius 35 km. Accounting for ... in the following as random hopping, different co-channel cells use different uncorrelated sequences, resulting in the desired interference diversity. According to Refer- ence [81], these seque...

Ngày tải lên: 24/10/2013, 16:15

... Mbytes, normally feature a distinctly elongated tail. Correspondingly, mean email sizes are large. Therefore, a prime candidate distribution to model email size is the Pareto distribution. There are, ... expanding on a paper from 1976 [244], he provided expressions for the variance in direct-sequence CDMA (DS/CDMA) systems, with random coding and BPSK modulation, as a function of the spreadin...

Ngày tải lên: 28/10/2013, 23:15

... contention mode between individual cycles. 6.3 MD PRMA with Time-Division Duplexing 6.3.1 Approaches to Time-Division Duplexing There are two fundamental approaches to providing time-division duplexing ... possible. 6.2.3.2 Differences in the Random-Coding Case There are subtle differences in the contention procedure for the ‘pure’ random-coding case. Since no code-slots are discriminated, th...

Ngày tải lên: 28/10/2013, 23:15

... scheme (assuming immediate acknowledgement); • the added traffic in the case of interleaving (I/L) due to dedicated request bursts and on average two additional bursts per voice spurt due to rounding up the ... performance of this protocol are discussed in Reference [37]. 2 This problem did not arise in Chapter 7, since a terminal, while holding a reservation in a certain time-slot, did not re...

Ngày tải lên: 07/11/2013, 21:15

... stack-based algorithms have the disadvantage of requiring immediate (although normally only binary) acknowl- edgements to work properly, which, as discussed at length earlier, is difficult to achieve in ... cannot be chosen individually, which is why this approach was termed semi-proportional rather than ‘non-proportional’ priority distribution. The lower the value of k, the larger the differe...

Ngày tải lên: 07/11/2013, 21:15

... categorised as either dedicated or common physical channels. 10.2.2.1 Dedicated Physical Channels All dedicated physical channels feature a radio frame length of 10 ms, with each frame subdivided into 15 ... than one DTCH can be mapped onto a single DCH, but different DTCHs can also be mapped onto different DCHs, depending on how the relevant radio bearers are configured. 10.2.2 Physical Chann...

Ngày tải lên: 15/12/2013, 06:15