This document discusses several key aspects of cellular network architecture and technology: - Traditional mobile networks used one powerful transmitter, while cellular networks use many low-power transmitters divided into cells to increase capacity and allow handoffs between transmitters. - Modern networks divide both rural and urban areas into cells using specific deployment guidelines. - Mobile networks employ different multiple access techniques including FDMA, TDMA, and CDMA to allow multiple users to access the network simultaneously.

1. 1. Early Mobile Telephone System Architecture
Traditional mobile service was structured in a fashion similar to television broadcasting: One
very powerful transmitter located at the highest spot in an area would broadcast in a radius of up
to 50 kilometers. The cellular concept structured the mobile telephone network in a different
way. Instead of using one powerful transmitter, many low-power transmitters were placed
throughout a coverage area. For example, by dividing a metropolitan region into one hundred
different areas (cells) with low-power transmitters using 12 conversations (channels) each,
Cellular system architecture
In modern cellular telephony, rural and urban regions are divided into areas according to specific
provisioning guidelines. Deployment parameters, such as amount of cell-splitting and cell sizes,
are determined by engineers experienced in cellular system architecture.
b) Cellular mobile Networks Use different techniques to implement Multiple Access. Describe the
three main technique
1. Frequency division multiple- fdma is the most straightforward of the multiple access schemes
that have been used. as a subscriber comes onto the system, or swaps from one cell to the next,
the network allocates a channel or frequency to each one. in this way the different subscribers are
allocated a different slot and access to the network. as different frequencies are used, the system
is naturally termed frequency division multiple access. this scheme was used by all analogue
systems.
2. Time division multiple-access(tdma) short for time division multiple access,a technology for
delivering digital wireless service using time- division multiplexing. Tdma works by dividing a
radio frequency into time slots and then allocating slots to multiple calls. in this way,a single
frequency can support multiple, simultaneous data channels. Tdma is used by the gsm digital
cellular system.

2. 3. Code division multiple-access- each user is assigned a unique pin code. in cdma, the same
bandwidth is occupied by all the users,however they are all assigned separate codes,which
differentiates them from each other. Users are separated by code not by frequency or time.
Wireless LANS and Cable Ethernet LANS have several similarities and differences. Describe briefly
the key differences
WLAN Ethernet LAN
The WLAN devices are based on IEEE 802.11 family
of standards.
The Ethernet LAN devices are based on IEEE
802.3 standards.
WLAN devices use high energy radio frequency
waves to transmit the data.
Ethernet LAN devices use electric signals to
transmit the data.
Radio frequency waves travel in the space. Hence a
physical connection is not needed between the devices
which are connected to the WLANs.
Electric signals flow over the cables. Hence wired
connection is needed between devices which are
connected to the Ethernet LANs.
WLAN uses half duplex mechanism for
communication.
Ethernet supports full duplex mechanism for
communication when a switch connects using a
single device rather than hub.
WLANs suffer from interference of various types
during travel from source to the destination.
LANs suffer less interference as electric signals
travel using cables.
WLANs use CSMA/CA to avoid collisions in the
network.
Ethernet LANs use CSMA/CD to detect collisions
in the network.

3. Outline the different generations of Cellular Mobile Network with respect to Data rates
1.SECOND GENERATION (2G)
2G refers to the second generation of mobile networks based on GSM. The radio signals used by
the 1G network were analog, while 2G networks were digital. 2G capabilities were achieved by
allowing multiple users on a single channel via multiplexing. During 2G, cellular phones were
used for data along with voice. Some of the key features of 2G were:
1. Data speeds of up to 64 kbps
2. Use of digital signals instead of analog
3. Enabled services such as SMS and MMS (Multimedia Message)
4. Provided better quality voice calls
5. It used a bandwidth of 30 to 200 KHz
2. THIRD GENERATION (3G)
The 3G standard utilises Universal Mobile Telecommunications System as its core network
architecture. 3G network combines aspects of the 2G network with new technologies and
protocols to deliver a significantly faster data rate. By using packet switching, the original
technology was improved to allow speeds up to 14 Mbps. It used Wide Band Wireless Network
that increased clarity. It operates at a range of 2100 MHz and has a bandwidth of 15-20 MHz.
Some of the main features of 3G are:
1. Speed of up to 2 Mbps
2. Increased bandwidth and data transfer rates
3. Send/receive large email messages
4. Large capacities and broadband capabilities
3. FOURTH GENERATION (4G)

4. The main difference between 3G and 4G is the data rate. There is also a huge difference between
3G and 4G technology. The key technologies that have made 4G possible are MIMO (Multiple
Input Multiple Output) and OFDM (Orthogonal Frequency Division Multiplexing). The most
important 4G standards are WiMAX and LTE. While 4G LTE is a major improvement over 3G
speeds, it is technically not 4G.
1. Support interactive multimedia, voice, video.
2. High speed, high capacity and low cost per bit 20 mbps.
3. Global and scalable mobile networks.
4. Ad hoc and multi-hop networks.
Describe the at least four components of a Cellular Network
a) Mobile Station (MS)
A mobile station is basically a mobile/wireless device that contains a control unit, a transceiver
and an antenna system for data and voice transmission. For example, in GSM networks, the
mobile station will consist of the mobile equipment (ME) and the SIM card.
b) Air Interface Standard
There are three main air interface protocols or standards: frequency division multiple access
(FDMA), time division multiple access (TDMA) and code division multiple access (CDMA).
These standards are basically the medium access control (MAC) protocols that define the rules
for entities to access the communication medium. These air interface standards allow many
mobile user to share simultaneously the finite amount of radio channels.
c) Base Station (BS)

5. A base station is a fixed station in a mobile cellular system used for radio communications with
mobile units. They consist of radio channels and transmitter and receiver antenna mounted on a
tower.
d) Databases
Another integral component of a cellular system is the databases. Databases are used to keep
track of information like billing, caller location, subscriber data, etc. There are two main
databases called the Home Location Register (HLR) and Visitor Location Register (VLR). The
HLR contains the information of each subscriber who resides in the same city as the mobile
switching center (MSC). The VLR temporarily stores the information for each visiting subscriber
in the coverage area of a MSC. Thus, the VLR is the database that supports roaming capability.
A cellular communication network is one that uses a large number of low-power wireless
transmitters to create cells. Each cell is fixed only for its service area, and not for the service
users, ensuring mobility. The addition of new cells into the network is also a fairly simple
process, promoting modularity in expansion.