Wireless Networks Questions Paper Example

Question 1

MAC is a short abbreviation that stands in place for Media Access Control address. It is a number, binary in this case, that specifies network adapters of computers distinctively. The number is unique and the address does not change whenever connections are made in different locations. The MAC address acts a unique identifier that bares a hardware address for every node within a network.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Save 25%

There are numerous MAC protocols that have been designed for sensor evaluation. However, there is no protocol that has been set as a standard for evaluation. The evaluation for wireless sensor networks and traditional MAC is thus different. This is so; since the choice of protocol to be used is specific to a particular application. Standardization at lower layers lacks which automatically disqualifies a standard protocol in the higher level.

Question 2

A hidden terminal problem; it is a scenario that manifests when 3 nodes are involved. 2 of the nodes are transmitting their signals to one node, centrally located but they are all hidden from each other. It is thus caused by transmissions that are simultaneous to both nodes, cannot hear each other but share the same recipient station.

For exposed terminal problem; it takes place when sent packets from a node, destined to other nodes, is blocked by a transmitter that is neighboring. The node is thus said to be exposed.

Comparison: Both terminal problems are known to have a negative impact on wireless communications as they degrade the computing potential service.

Contrast: hidden terminal problems are characterized with numerous message collisions; the transmitters are outside each other's range while for exposed terminal problems, collisions are not experienced but, the messages are delayed due to the occupation of the medium by other transmissions.

Question 3

RTS (Request to send) and CTS (Clear to send) are protocols that have been developed to bring about efficiency in wireless network's operations, as they collisions are being avoided. These mechanisms, reserve the transmitting channel between the destination and the source of the node. Hidden nodes are the major causes of collisions and directly affect transmission outputs. The RTS/CTS set timers for the nodes within the neighborhood so that they can pause their transmissions until the set packet data transmission period expires. RTR packets are sent by the receiving node as it notifies neighbor nodes of the communication exhaustion. With effective communication and coordination from the CTS and RTS data transfer efficiency is optimized. This mechanism is anchored under the Multiple Access Collision Avoidance whose aim is tackling the hidden terminal problem. It works systemically; when a node needs to send data, it has to send an RTS signal to the recipient node, the other nodes that hear the signal, defer their transmissions to allow communication and transmission between the cleared nodes. However, it is notable that at times delays occur when the transmission is completed before the set time.

Question 4

FDMA: frequency division multiple access; it is considered as a foundational technological basis for cellular services. Different users can access the network as they are allotted sub-band frequencies that are different. Its implementation is in narrowband systems and is less complicated when compared to TDMA. When not in use, the channel lies idle. Channel interference is reduced by tight filtration. BS and MS receive and transmit simultaneously and continuously.

TDMA: Time Division Multiple Access, it does not support continuous transmission. A single carrier frequency is shared by several users. Advantageous as it allocates different time durations to different users.

CDMA: Code Division Multiple Access, a single channel supports many transmitters to simultaneously share information. Each user uses a whole spectrum. Users with the same code can intra-communicate. It boosts a superior air-space capacity to TDMA.

SDMA: Space Division Multiple Access uses satellite communication. It is superior to others In that; every user can communicate at any time, it is fully devoid of interference. Intra-satellite communications and can regulate energy radiations from the sun.

I would prefer SDMA for WSN; the coverage by SDMA is wide enough and only needs a device to get a signal, the use is not restricted. The assumption here is that geographical barriers can be turned to be agents of satellite positioning.

Question 5

The CSMA (Career sensed Multiple access); is a method of accessing network that has been shared. The network's devices get senses through which they transmit. Since it is a multiple access platform, many devices can use it concurrently, and access to the network is equal. It is principally based on 'carrier sense.' Delays in propagation bring about collision chances.

Question 6

The LEACH protocol is a hierarchical approach that routes for efficiency techniques that lower consumption of energy by aggregating data and data fusing to reduce base station transmissions. It vouches for clustering of sensor nodes based on their strength and cluster heads sink. In this, the energy consumed is enhanced because it is the cluster heads do transmission and not the sensor nodes. This protocol is based on adaptation, clustering, and organization. It helped in enhancing the lifetime of a network and enhanced energy consumption by allowing cluster heads to do transmission rather than the nodes.

Question 7

Framing involves the breaking of a continuous bit-stream into smaller frames. It is necessitated by the need to detect errors or to control chunks of work. The methods involved include: counting characters, prone to error, stuffing characters by frame limitations and timing which is risky since it does not guarantee network.

Control flow. The throughput is maximized; the receiver is not flooded by the sender though.

The control link management protects the credibility of the whole system. It encompasses control of flow, error control and framing. It is tasked with the recovery of errors and takes care of acknowledged and unacknowledged services.

Question 8

ARQ's advocates for reliable transmission of data by providing avenues that guarantee it. They ensure that the transferred data is reliable as they are applied in the error control systems. The protocols are three in number; GBN, SR, AND SW. The protocol controls error by retransmitting data packets if an inconsistent data is received. It makes use of acknowledgment signals.

The forward error correction is effected when the acknowledgment signal is not relayed. For the autocorrect, errors that are detected are rectified before the commencement of transmission.

Question 9

No. A fully connected network may be controlled by maximum transmission power. However, the same is highly sensitive to temperature fluctuations. Having overhead packets for control and maintaining the quality of the link needs an elaborate mechanism to act as a control. Sensor nodes do well in areas where temperature fluctuations are rampant. An increase in temperature decreases the value of Received Signal Strength Indicator. There is also the risk of increased overhead.