ABSTRACT-Video increasing usage in daily activities, importantly for

ABSTRACT-Video transmission in a wireless network hasbeen available for quite some time and their increasing usage in dailyactivities, importantly for work related matters have demanded a stable outlet.

There is no guarantee at the point of reception for the correct ordering ofpackets of data, and for processing of data in a smooth manner so that thevideo will proceed without interruptions. While there few methods that haveimproved transmission greatly, there are still problems like improving thethroughput wireless LAN. In the analysis it has been proved that the layeredapproach takes too much time to provide seamless transmission.

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!

order now

Thus a crosslayered approach has been adopted in which the focus will be on the physicallayer, the MAC layer and the application layer. Signal to Noise Ratio (SNR) isa property of wireless networks that is used to measure the most optimum rateof transmission as there are several transmission rates according to the deviceused. The transmission rate will be determined using Rate Adaptation Algorithm.The transmission rate at the application layer is then synchronized with theMAC layer using Adaptive Encoding.

This proposed analysis will be useful inmeasuring the most optimum transmission rates followed by an effective adaptiveencoding process, thereby improving the throughput of IEEE 80211n WLAN. I.                   INTRODUCTION YangXiao and et all (2013) survey the available cross-layer designs. Classificationis done with respect to two structures one based on the information sharingbetween the nodes and other based on the organization of the network.

Based onthe information sharing between the nodes it is divided into two categories-Manager and Non-Manager Method. Manager method uses the Control program whichacts as a transmission medium for sharing information between the layers.Non-Manager method passes information without any medium creating an illusionthat every layer is adjacent to each other. Based on the organization of thenetwork it is divided into two types-Distributed method and Centralized method.The centralized method uses a centralized node or tier which is in ahierarchical manner to achieve communication between nodes. The centralizedmethod is typically used in cellular networks. Thedistributed method does not use any centralized node or tier.

The distributedmethod is typically used in ad-hoc networks 1.              Gabriel Martorell et all (2009)uses a Cross-Layer Fast Link Adaptation (FLA). Optimization is done in bothTransmitter side and Receiver side. An FLA technique based on packet error rate(PER) that makes use of the exponential effective SNR mapping (EESM) is used.Additionally, a bit error rate (BER) based FLA scheme is proposed thatsimplifies the calibration procedure without any significant performancedegradation.

Bit Error Rate in the Physical layer is used to determine thePacket Error Rate (PER) in which the Modulation and Coding Scheme (MCS) isselected, having least outage probability. Using PER, instantaneous throughputof the each MCS is calculated and the MCS with the least value is selected. Theprobability is the direct consequence of the objective function Pm = fm(SNR)  The MCS is chosen such that Pmis minimized. This MCS gives the optimal transmission rate 2.Rate Adaptation             Arafet Ben Makhlouf and et allproposed a Rate Adaptation algorithm called L3S.

Rate Adaptation algorithm isbased on a probing system that guarantees that it is has Long-Term Stabilityand Short-Term Responsiveness. The new rate adaptation classifies transient andsustained changes in the link conditions. Then, it controls both short-term andlong-term channel quality variations respectively by monitoring continuouslythe transmission history and intelligently probing at new data rates that mayoutperform the current rate. Short-term statistics are used to controltransmission rate at short time changes. It uses consecutive received and lostACK to determine the channel condition and decide the transmission rate.

Long-term statistics are maintained to adapt transmission rate, which providesbest throughput, against the long sustained changes. Transmission rate isadapted to senders state .Sender uses two states Tx state and Probe state.

Ineach round, the transmitter moves periodically between these two states andupdates continuously the associated statistics. Using these states MCS withhigh throughput is selected 3              Jiansong Zhang et all (2008) usesSNR for rate adaptation to counter the rate adaptation techniques whichinvolves frame losses. These frame losses algorithm doesn’t able todifferentiate channel error and interference losses. In this paper SNR isconsidered but SNR is an uncalibrated data so a novel Frame delivery ratioFDR-SNR bases prediction is uses as FDR as an optimistic optimization of SNR. First step is the online calibration of SNR in which the SNRlow and SNR high is calculated for the current transmission rate. Then the RateAdaptation algorithm checks if there is any interference in the channel if soan interference variable is set or interference free variable is set. If theinterference free variable is set then for each rate available the interferenceFDR* is calculated. Else the FDR is calculated as the function of SNR values oflow and high then the rate with maximum FDR is chosen and applied to the network4.

 Adaptive encoding             S.Khan et all (2006) proposed architectureat the application layer, the video encoder can also adapt to the link qualityby, for example, changing the compression degree and thus modifying the datarate. This adaptation requires that the video encoder be able to sense the linkquality (e.

g., by setting feedback information from the decoder side). Anadaptive encoding technique if used .The video codec used is an H.263 codecmodified to support interaction with the link layer.

The H.263 encoder supportsa video rate control algorithm (VRCA) that tries to achieve a certain rate byadjusting the quantization step size. The quantization step size is the mainparameter that controls the compression of the video. This VRCA has beendesigned for constant bit rate (CBR) encoding, but can also be used to dynamicallychange the bit rate produced by the encoder 5.


I'm Mary!

Would you like to get a custom essay? How about receiving a customized one?

Check it out