Tài liệu Nhiều giao thức truy cập đối với truyền thông di động P10 doc
Tài liệu Nhiều giao thức truy cập đối với truyền thông di động P10 doc
... 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...
Tài liệu Nhiều giao thức truy cập đối với truyền thông di động P11 docx
... apply UED and UEP accordingly
is only one important technique to improve the radio link performance, adapting the type
of voice coding depending on the current radio conditions is another one ... (e.g. by performing transcoding close to the radio link, that is converting
a radio-independent non-AMR bit-stream into an AMR-coded stream according to the
local conditions) or suitable end-to-end ....
Nhiều giao thức truy cập đối với truyền thông di động P1
... 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 ......
Nhiều giao thức truy cập đối với truyền thông di động P2
... 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...
Nhiều giao thức truy cập đối với truyền thông di động P3
... 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...
Nhiều giao thức truy cập đối với truyền thông di động P4
... 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...
Nhiều giao thức truy cập đối với truyền thông di động P5
... 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...
Nhiều giao thức truy cập đối với truyền thông di động P6
... 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...
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...
Nhiều giao thức truy cập đối với truyền thông di động P8
... 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...