WT Question Paper Solution (May 2023) – IT MU
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Q1. Solve any four (20 marks)
a. Explain any four features of MANET and compare MANET and WSN. (5 marks)
Ans-
A. Features of MANET (Mobile Ad-Hoc Network)
1. Infrastructure-less Network: MANETs operate without a fixed infrastructure, allowing nodes to communicate directly with each other.
2. Dynamic Network Topology: Similar to VANETs, MANETs have a dynamic network topology due to node mobility.
3. Self-Configuring: Nodes in MANETs are capable of self-configuring and organizing into a network without the need for centralized administration. 4. Limited Power and Bandwidth: MANETs often operate with limited power andbandwidth, requiring efficient communication protocols and resource management.
B. Comparison MANET and WSN
b. Write note on LTE frame structure in detail. (5 marks)
Ans-
1. Time duration for one frame (One radio frame, One system frame) is 10 ms. This means that we have 100 radio frame per second.
2. Let’s look at the frame structure:
● Number of slots in one subframe is 2. This means that we have 20 slots within one frame.
● And one slot is made up of 7 small blocks called ‘symbol’.
3. The frame structures for LTE differ between the Time Division Duplex, TDDandthe Frequency Division Duplex, FDD modes as there are different requirements on segregating the transmitted data
4. There are two types of LTE frame structure:
Type 1: used for the LTE FDD mode systems.
Type 2: used for the LTE TDD systems.
Type 1: FDD Frame Structure
As LTE FDD is full duplex system, means both the downlink and uplink transmissionhappens at the same time at different frequencies.
Type 2: TDD Frame Structure
In TDD, the transmission is divided into time domain, means at one moment of timeeither downlink subframe is transmitted or uplink.
As one can see in above image, one frame is divided into 10 subframes (1ms each), and that subframe can be either downlink, uplink or special subframe.
c. Describe evolution of 1G to 5G mobile systems. (5 marks) Ans-
The evolution of mobile communication from 1G to 5G represents a significant journey marked by technological advancements and paradigm shifts.
1. 1G (First Generation):
⮚ 1G marked the advent of mobile com., primarily focusing on analog transmission. ⮚ It enabled voice calls with limited coverage and quality, often characterizedbypoor reception and call drops.
⮚ The first commercially available 1G network was launched in Japan in 1979.
2. 2G (Second Generation):
⮚ 2G introduced digital transmission, offering better voice quality, security, andefficiency compared to 1G.
⮚ It facilitated the introduction of text messaging (SMS) and basic data services. ⮚ Technologies like GSM (Global System for Mobile Communications) andCDMA (Code Division Multiple Access) emerged during this era. 3. 3G (Third Generation):
⮚ 3G brought significant improvements in data transmission rates, enabling internet access, video calling, and multimedia services on mobile devices.
⮚ Technologies such as UMTS (Universal Mobile Telecommunications System) and CDMA2000 were deployed to provide higher data speeds.
⮚ This era saw the rise of smartphones and mobile internet usage.
4. 4G (Fourth Generation):
⮚ 4G represented a major leap forward, offering significantly faster data speeds, lower latency, and enhanced multimedia capabilities.
⮚ Technologies like LTE (Long-Term Evolution) and WiMAX(WorldwideInteroperability for Microwave Access) provided the foundation for 4Gnetworks. ⮚ It facilitated the widespread adoption of high-bandwidth applications likestreaming video, online gaming, and cloud services.
5. 5G (Fifth Generation):
⮚ 5G is the latest evolution in mobile communication, promising even faster dataspeeds, ultra-low latency, massive connectivity, and network slicing. ⮚ It utilizes advanced technologies such as millimeter-wave spectrum, massiveMIMO (Multiple Input Multiple Output), and beamforming.
⮚ 5G is expected to revolutionize industries with applications like autonomous vehicles, remote surgery, smart cities, and IoT (Internet of Things) devices.
d. Outline the method that supports mobility in CISCO Unified Wireless Network. (5 marks)
Ans
In Cisco Unified Wireless Network (CUWN), mobility is supported through a combination of protocols, mechanisms, and features that enable seamless roaminganduninterrupted connectivity for wireless clients as they move within the network. Here’s an outline of the key components and methods supporting mobility in CUWN:
1. Wireless LAN Controller (WLC) Integration: Cisco WLCs play a central role inmanaging the wireless network infrastructure. They control and coordinate the operations of access points (APs) and provide centralized management for mobility related functions.
2. Layer 2 Roaming: In CUWN, Layer 2 roaming allows wireless clients to roamseamlessly between APs within the same subnet or VLAN without changing their IPaddress. As clients move between APs, the WLC maintains session information andforwards traffic to the appropriate AP.
3. Inter-Controller Roaming: CUWN supports roaming across multiple controllers. When a client roams between APs managed by different controllers, the controllers exchange client session information to ensure continuity of service. This enables clients to roam between different parts of the network without losing connectivity.
4. Fast Roaming Protocols:
⮚ IEEE 802.11r (Fast BSS Transition): Accelerates the roaming process by pre- authenticating the client with neighboring APs, reducing the time required for reconnection.
⮚ IEEE 802.11k (Radio Resource Measurement): Enables APs to provide information about neighboring APs and network conditions, facilitating better roaming decisions.
⮚ IEEE 802.11v (BSS Transition Management): Allows APs to assist clients inmaking roaming decisions by providing information about available networks andcapabilities.
5. Client Stateful Roaming: Cisco WLCs maintain client session state information, including authentication and encryption context. This allows for smooth handoff as clients roam between APs, ensuring that session continuity is maintained without requiring reauthentication.
6. Optimized Roaming Policies: Administrators can configure roaming policies onWLCs to control client roaming behavior based on factors such as signal strength, load balancing, and AP utilization. These policies help optimize roaming decisions and enhance overall network performance.
7. Wireless LAN Controller Redundancy: CUWN supports controller redundancyto ensure high availability. Redundant controllers synchronize configuration and client session information, allowing for seamless failover in case of controller failure.
e. Write note on CDMA2000. (5 marks)
Ans-
CDMA2000 is a code division multiple access (CDMA) version of IMT-2000 specifications developed by International Telecommunication Union (ITU). It includes a group of standards for voice and data services − 1. Voice − CDMA2000 1xRTT, 1X Advanced
2. Data − CDMA2000 1xEV-DO (Evolution-Data Optimized)
CDMA2000 Standards:
The following are CDMA2000 standards:
1. CDMA2000 1xRTT: Supports data as well as voice at up to 144 kbps data speeds. 2. CDMA2000 1xEV-DO: Offers faster data rates, up to 3.1 Mbps, and is primarilyused for data services.
3. 1xEV-DV CDMA2000: Combines voice and data while also providing high-speedconnectivity.
4. CDMA2000 3x: A portion of IMT-2000, as defined by the ITU Multiple Carrier CDMA
5. CDMA2000 1x: Generally regarded as a 2.5G technology
CDMA2000 Core Network:
CDMA2000 is a 3G network that transmits voice, data, and other information usingaset of standards.
Additionally, it can be used to access a 2G network because it is backward compatible.
An upgraded air interface in the CDMA2000 system allows CDMA to operate over larger bandwidths for increased capacity and data speeds. Additionally, it preserves backward compatibility with end-user IS-95 CDMA devices currently in use. Data is sent by CDMA2000 systems using quadrature phase shift keying, or QPSK.
Features of CDMA 2000
1. CDMA2000 is a family of technology for 3G mobile cellular communications for transmission of voice, data and signals.
2. It supports mobile communications at speeds between 144Kbps and 2Mbps. 3. It has packet core network (PCN) for high speed secured delivery of data packets. 4. It applies multicarrier modulation techniques to 3G networks. This gives higher
data rate, greater bandwidth and better voice quality. It is also backward compatible with older CDMA versions.
5. It has multi-mode, multi-band roaming features.
