12-12-2012, 05:46 PM
can u send me the base paper and code for that
12-12-2012, 05:46 PM
can u send me the base paper and code for that
05-07-2013, 11:09 AM
sir i am working on dwt image over ofdm fadding channel with csi adaptation model to control the power please send me the matlab source for energy efficient transmission of dwt image over ofdm fading channel
thanking you sir
08-07-2013, 10:36 AM
To get full information or details of energy efficient transmission of dwt image over ofdm fading channel please have a look on the pages
http://seminarprojectsshowthread.php?tid=54429&google_seo=r8w4++&pid=108420#pid108420 https://seminarproject.net/Thread-transm...-media-pdf if you again feel trouble on energy efficient transmission of dwt image over ofdm fading channel please reply in that page and ask specific fields
07-03-2014, 10:09 AM
sir please send me ppt of enrgy efficientt image transmission over ofdm using huffman
08-03-2014, 10:37 AM
To get full information or details of energy efficient transmission of dwt image over ofdm fading channel please have a look on the pages
https://seminarproject.net/Thread-energy...hannel-ppt if you again feel trouble on energy efficient transmission of dwt image over ofdm fading channel please reply in that page and ask specific fields
26-04-2014, 11:24 AM
Energy-Efficient Transmission of DWT Image over OFDM fading Channel Energy-Efficient Transmission.pdf (Size: 338.09 KB / Downloads: 17) Abstract In many applications retransmission of lost pack- ets are not permitted. In an OFDM system, due to channel fading, only a subset of carriers are usable for successful data transmission. If the channel state information is available at the transmitter, it is possible to take a proactive decision of mapping the descriptions optimally onto the good subcarriers and discard at the transmitter itself the remaining descriptions, which would have been otherwise dropped at the receiver due to unacceptably high channel errors. In this paper we present a energy saving approach to trans- mission of discrete wavelet transformation based compressed image frames over the OFDM channels. Based on one-bit channel state information at the transmitter, the descriptions in order of descending priority are assigned to the currently good channels. In order to reduce the system power consumption, the mapped descriptions onto the bad subchannels are dropped at the transmitter. Via analysis, supported by MATLAB simulations, we demonstrate the usefulness of our proposed scheme in terms of system energy saving without compromising the received quality in terms of peak signal-noise ratio. INTRODUCTION It is always desired to increase the data rate over wireless channels. But high rate data communication is significantly limited by Inter Symbol Interference (ISI) and frequency selective fading nature of the channel. Rayleigh fading channel is an example of frequency selective and time varying channel. Multi-carrier modulation is used for such channels to mitigate the effect of ISI. OFDM is a multi-carrier modulation scheme having excellent performance which allows overlapping in frequency domain. In OFDM, individual subchannels are affected by flat fading, so for a period of time, condition of the subchannels may be good, or they might be deeply faded. The packets which are transmitted through these faded subchannels are highly prone to be lost at the receiver due to non-acceptable errors. OFDM system provides an opportunity to exploit the diversity in frequency domain by providing a number of subcarriers, which can work as multiple channels for applications having multiple bit streams SYSTEM MODEL In our system model, an image frame is compressed using DWT, and the compressed data is arranged in data vectors, each with equal number of coefficients. These vectors are quantized and binary coded to get the bit steams, which are then packetized and intelligently mapped to the OFDM system, such that poorer subchannels can only affect the lesser important data vectors. We consider only one-bit channel state information available at the transmitter, informing only about the subchannels to be ‘good’ or ‘bad’. For a good subchannel, instantaneous received power should be greater than a threshold Pth . Otherwise, the subchannel is in fading state and considered ‘bad’ for that batch of coefficients. Note that the data transmitted through deeply faded subchannels are highly prone to error and are likely to be discarded at the receiver. Channel model: In this study we use block fading channel model as in [8]. The channel model is illustrated in Fig. 3, where M is the coherence bandwidth in terms of number of subchannels. In a block fading environment, M consecutive subchannels will simultaneously be either bad or good. Each such set consisting M subchannels is called a ’sub-band’. We denote total number of such sub-bands in the OFDM system as N . Thus, the total number of subchannels in the system is N × M . All sub-bands are independently faded with Rayleigh-distributed envelop, which corresponds to the block fading approximation in frequency domain [9], [10]. Our proposed mapping scheme generates a situation of subcarrier assignment for each data vector in a packet. Analysis of this environment is presented in Section III. FORMULATION AND ANALYSIS We now formulate the average distortion and energy savings in our proposed transmission scheme. We measure the system performance by probabilistic analysis of the average distortion in a block fading environment. CONCLUSIONS To conclude, we present a case of DWT compressed image transmission over OFDM channels where binary channel state information is available at the transmitter, but retransmission is not allowed. We propose a energy saving approach, where the compressed coefficients are arranged in descending order of priority and mapped over the channels starting with the good ones. The coefficients with lower importance level, which are likely mapped over the bad channels are discarded at the transmitter to save power without significant loss of reception quality. Our analytic observations on reception quality and en- ergy saving performance are validated by extensive MATLAB simulations. As a future work, we plan to extend the current study with CSI adaptive channel rate as well as power control to find a more generalized trade-off between transmission rate and energy saving in image as well as video transmission applications. |
|