Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

What do you mean by Extended Cell? Does it
have any impact on the system? If yes, what?
a) Extended cell feature enables the operators for extending the coverage without installing new cell
cites
...

c) New features can be deployed in coastal areas for providing GSM coverage in offshore waters
d) It’s impact is:
- The cell radius could be double or even more, based on the antenna, type of terrain and timing
advance
- Indoor coverage is supported by GSM and could be achieved with the usage of picocell base station
or an indoor
repeater along with distributed indoor antennas
...

- The subscriber is paged in this area
- One or more base station controllers are used to serve each Location Area but by a single MSC
...

- Each mobile is needed to report regularly its location at a given time of interval by using a periodic
location update
process
...

- Hence, the subscriber has reliability to access the network and freedom of mobility within the
coverage area
...

- ARFCN is used for transmitting and receiving on the UM Interface, one to uplink signal and one to
downlink signal
...
833 kHz; channel spacing is 200 kHz in a given GSM band
...

- If Frequency Division Duplex is operated in the system, then the channel number is associated with
both
uplink and downlink radio channels
...

What is power control?
- Power control is the intelligent selection of transmit power in a communication system for achieving
best
performance within the system
- The performance is depend on context and there are chances to include optimizing metrics like link
data
rate, network capacity, geographic coverage and range
- A higher transmit power translates into a higher signal power at the receiver
- The bit error rate will be reduces at the receiver of a digital communication link, by having higher
signalto-noise ratio
- Higher transmit power provides more protection against a signal fade in a wireless fading channel
...
)FDD
b
...

- To uplink the carrying data from mobile phones to the base station, one electromagnetic
block spectrum is allocated
- Various blocks of spectrum is allocated to downlink carrying data from the base station
to the mobile telephone hand sets

b) TDD
- Time Division Duplexing, a 3GPP standardized version of Universal Mobile
Telecommunications System networks
...
What is the maximum data rate supported by a
GSM system?
- The maximum data rate supported by a GSM system is 9
...

- However there are extensions to GSM standard to improve throughput
...

- The extended standards of GSM allows theoretical data rates on the order of 114 Kbit/s, but with
throughput closer to 40Kb
practice
...
)
Sectorization of a cell b
...
) Transmitted Power

Control d
...
) Sectorization of a cell
- Sectorization is a process to cut down equipment costs in a cellular network
...


b
...

- Different frequencies are utilized by adjacent cells; however problem does not arise to
determine the cell sufficiently far apart using the same frequency
...


c
...

- TPC reduces interference problems and increases the battery capacity
- The power levels of a single mobile device can be reduced by 6dB

d
...

- The overall efficiency of a wireless voice communication system is optimized by DTX
...

- The workload of the components in the transmitter amplifiers are made easy and reduces
interference
...
) Which uplink/ downlink spectrum is allocated to following? a
...
) DCS – 1800
c
...
) GSM – 900: Uplink spectrum is 890
...
8 and downlink spectrum is 935
...
8
b
...
2–1784
...
2–1879
...
) Name the algorithms used in following: a
...
) Authentication
e
...
) Ciphering
- The algorithm 129-EEA3 and 128-EIA3, 3GPP Confidentiality and Integrity Algorithm is used for
ciphering in GSM
b
...

Frequency Re-use:

- Frequency re-use is one of the techniques for improving capacity and spectral efficiency
...

- A frequency that is far enough away from the frequency in the bordering segment is used by one
segment of the cell
...

- This practice enables various cellular providers to have several customers for a given site license
...
) BTS and MS b
...
) BSS and MSC d
...
)
BSC and PCU
a
...
- Transcoding of
speech channels are carried out by BSS
...

b
...
A BSC conrolls hundreds of
BTSs
...

- BSC controls BTS to BTS
...

- BSC provides the required data to operation support subsystem(OSS) and also to the
performance measuring centers
- BTS supports the key features like, frequency hopping, sectorization, and GPRS
...

- The power output of BTS is up to 80W
...
) BSS and MSC
- BSS will send the called number to MSC(Mobile Switching Center)
- MSC checks the VLR and queries BSS for allocation of resources for the cell
- Then MSC routes the call to GMSC
- Switching nodes for base station controls is done by MSC
d
...

- BSC and TRAU does not demand specific environmental conditions to perform operations
...

- BSC supports various BSC-BTS configurations like star, multidrop and loop, and star

configurations towards TRAU
- TRAU is a stand alone unit which could be located close to a MSC(Mobile Switching Center),
which enables the optimum utilization of 16 kbit/s channel sub multiplexing and saves line costs
...
) BSC and PCU
- The Packet Control Unit is an adaptor / handler unit which enables GPRS and EDGE
functionality within Radio Access Network
...


b
...
) Synthesised Frequency Hopping, b
...
) Cycling Frequency Hopping
c
...
) Synthesised Frequency Hopping
- The GSM’s number of frequencies is 124- When the operators do not have enough frequencies, the
range to be used is CDS 1800
- Frequency hopping is used when the frequencies used are more with high interference
...

- One of the frequency hoppings is Synthesised Frequency Hopping
...

Because of this process SFH is known as fast hopping
...
) Base Band Frequency Hopping
- Base Band Frequency Hopping is one of the frequency hopping techniques
...

- In this, static transceiver frequencies are used while operating with broadband transceiver
...

c
...

- For ex: f1,f2,f3
...

- Hopping Sequence Number is set to 0 in a cyclic sequence hopping
- The sequence of frequencies starts from the lowest absolute frequency number in a set of
frequencies specified for a specific channel group, to highest absolute frequency number
...
) HSN b
...
) DRX – TRX
a
...

b
...

The transmitter is turned off when a voice signal is misinterpreted as noise
...

c
...

 DRX performs the transmission and reception of signals
 Sends and receives the signals to or from higher network entities, as in base station controller in
mobile telephony
TRX:
 The transceivers allows to serve several frequencies and different sectors of the cell
 Sends and receives signals from / to higher network entities

---