Data and Image Transmission on DS-PAM UWB System in Parallel ...

International Research Journal of Applied and Basic Sciences © 2014 Available online at www.irjabs.com ISSN 2251-838X / Vol, 8 (6): 717-726 Science Explorer Publications

Data and Image Transmission on DS-PAM UWB System in Parallel Links AWGN Channel Using Multiple Description Coding (MDC) Ali Arshaghi1, Mehdi Nooshyar2,Mansour Selseleh Jonban3, Ahmad Hatam4 1. Young Researchers and Elite Club, Majlesi Branch, Islamic Azad University, Isfahan, Iran 2. Electrical Engineering Department, Faculty of Engineering, University of MohagheghArdebili, Ardabil, Iran 3. Young Researchers and Elite Club, Ahar Branch, Islamic Azad University, Ahar, Iran 4. Computer Engineering Department, Faculty of Engineering, University of Hormozgan, Hormozgan, Iran *Corresponding Author email:[email protected],[email protected], [email protected],[email protected]

ABSTRACT:UWB communication system is a new high performance technique with low power consumption which it has a large application for very high data rates in wireless telecommunications.In this paper, we consider image transmission in UWB system with parallel links AWGN noise channel using multiple description coding (MDC) technique. This idea is new, and so far there is no record of it. First, direct sequence ultra wide band performance techniques are analyzed for AWGN channels. Image transmission is then implemented with multiple description coding and with no multiple descriptions coding of image.The method of multiple description coding ensures thatthe version that the loss does not need to retransmit the missing versionand acceptable quality of image obtain against the channel errors. Send a picture of the proposed system with different number of transmitter and receiver antennas have been numerous experiments confirm the success of the method. Experimental results show that the desired goals are reached. Keywords:Direct Sequence, UWB, AWGN, MDC. INTRODUCTION Due to the relatively large volume of data in image transmission and non-uniform information bits than data transmission are greater challenges. Image transmission can be more challenging in the wireless environment. In mobile networks, satellite networks, wireless sensor networks and contingency, images (and video) are sent on the wireless channel. Techniques of ultra wide band are suitable to use in image and video transmission. Telecommunication Wireless multimedia plays an important role in recent years; for this reason, there are so many applications to use image transmission wirelessly. Ultra Wideband (UWB) technology can be appropriate solutions for telecommunication wireless high-speed whit short-range. The radio technology can be with a bandwidth of 25% of the center frequency. Power UWB system is Low in band frequency, because, it can play in a wide frequency band. The immune system in front of distortion and interference is a high contrast and time resolution in the receiver is very good. Low complexity and cost of the technology are important advantages that it make possible to use mobile application. In these systems, instead of sinusoidal carriers, very narrow pulses are transmitted, and system bandwidth will appear in several GHz (Emami, 2013). There are various developments of communications standards based on UWB technology (DiBenedetto et al., 2006; Ghavami et al. 2004; Yang et al. 2004; Qiu et al., 2005). UWB signal have unique features e.g., extremely high data rates (500 MBit/s for wireless USB), precise ranging and relocation (for many sensor networks) (Gezici et al., 2005), Two basic methods are offered for ultra wide band which include Time Hopping UWB (TH-UWB) technique and direct sequence ultra wide band (DS-UWB) technique. So far, most researches in the field image transmission of UWB systems consist of two techniques direct sequence ultra wide band whit modulation antipodal (DS-UWB) and time hopping method by modulation

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

PPM (TH-UWB) (Lv et al. 2010; Okiljevic et al., 2011). Other researches are performed in AWGN channel, and the performance of UWB system is compared with the modulation and different Access method. The results show that the DS-UWB systems with antipodal modulation can be had better performance with less complexity than TH-UWB system with Pulse Position Modulation (PPM) modulation (Bai et al., 2005; Zhang et al., 2005; Kshetrimayum et al., 2009). Multiple Description Coding (MDC) technique is a technique that is suited to wireless environments where the risk of losing data. These techniques are used in order to more protect on image transmission and resist transmitted data on the wireless channels. MDC in contrast competing methods such as Multi-Layer Coding (MLC) or Joint Source Channel Coding (JSCC), that they were implemented in every case research for various channel models (Wang et al. 2005). This paper presents image transmission on the channels of ultra wide band using multiple description coding and modulation PAM (DS-UWB) with direct sequence technique, accomplish in pass from parallel links AWGN channel. Transmission of multiple description images with parallel links noise channel in UWB is a new research that it was not already done. Wireless channel model have been considered AWGN with attention to former researches that was used from AWGN channel (Xu et al. 2006). The simulation results are compared with the method of MDC and single description coding (SDC). The rest of this paper is organized as the following: In Section 2 we investigate the model’s DS-UWB system with PAM modulation. In Section 3 we discuss multiple descriptions coding of the image and its implementation. Parallel links AWGN channel is described in Section 4. In Section 5 the results of several simulations are presented by changing the parameters that is influence in the implementation of the ideas which are achieved in this article. Finally, in Section 6 includes conclusions and ideas for future work. DS-UWB System Model Transmit Signal DS-UWB System We give a direct sequence spread spectrum UWB system with multiple accesses of NU users. Block diagram DS-PAM UWB system for one user is shown in Figure(1). T Each user has a pseudo-noise sequence for every data symbol (with period of f ) with N c the chip so that:

N cT c  T f (1) where NC is the spread spectrum processing gain. th The received signal of the k user at the receiver can is equal with (Bai et al., 2005):

k t   s tr

  Nc 1   d kj C nk wtr t  j T f  n T c j   n  0



 (2)

 

wherejis the frame number, t is independent parameter time, T f is period symbol of the message, D jk  is the d jk  th th binary information bit, is the modulated data symbols by k user in j frame with d jk   2 D k  , N is the  j N s S k  is spread chips andW tr(t)is the transmitted monocycle waveform pulse repetition time, T c is the chip time and C n (Bai et al., 2005).

 

Received Signal th Received signal by K user at the receiver is equal to (Bai et al., 2005): r t  

Nu k  t    A k s rec k k 1

(3)

718

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

Figure 1. Transmission diagram of the DS-PAM-UWB System

k  t   k  th where AK Suggests attenuation received signal s rec from K transmitter.  k is the propagation delay

between the transmitter and receiver and n(t) the AWGN noise that modeled as N 0 ,  n  . Number of transmitters and signal amplitude ( Ak ) is assumed constant. The main assumption is gotten by ideal channel. Any signal only suffered one weakening and the delay is constant. A system with the ideal channel transmit pulse waveform W tr varies to transferred pulse waveform W rec into the receiver which effects on transmitter and receiver antennas. In Reference (Somayazulu, 2002; Win et al., 2000), the following mathematical model for the received narrow pulse waveform is proposed. 2

2 2   w rec t  T w / 2   1  4  t /  m   exp   2  t /  m      

(4)  where TW is the pulse duration and m pulse width parameters. This model is obtained based on empirical measurements and the waveform is shown in Figure (2). Multiple description coding is a source coding technique that protects the image quality in front of the errors of the channel. From original image is made 4 sub-images with MDC method using subsampling method. Subsampling methods is that from the original image are separated circle pixels into Version 1 and square pixels into Version 2 and the rhombus-shaped into version 3 and stars pixels into version 4. Figure 4 shows it. MULTIPLE DESCRIPTION CODING MDC technique is presented as a good way to add features to deal with errors in the video system and images transmission. Wolf and Ozarow were the first scholars that discuss on the MDC in the early decade 1980, (Vaishampayan, 1993; Franchi et al., 2005). In this paper is studied source of data coding for sending on two OnOff Channels and decoding them by three receivers. Multiple description coding is shown in Figure (3)(Lin et al., 2007).

Figure 2. A narrow pulse waveform received by the relationship (3) Model DS-UWB systems

719

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

Figure 3. Block diagram of a multiple description coding system based on DCT (Lin et al., 2007) Multiple description coding is a source coding technique that protects the image quality in front of the errors of the channel. From original image is made 4 sub-images with MDC method using subsampling method. Subsampling methods is that from the original image are separated circle pixels into Version 1 and square pixels into Version 2 and the rhombus-shaped into version 3 and stars pixels into version 4. Figure (4) shows it.

Figure 4.Polyphase Subsampling in place domain (Image)

Made sub images in transmitter to subsampling method in MDC is shown in Figure (5).

ba

c d Figure 5. Made sub images in transmitter In Figure (6) is drawn a block diagram of the overall four description coding. According to figure 6 original input images is divided to four versions data that is called the version (sub-image). Each of versions separately has satisfactory quality of the original image. If all of versions are received at the receiver, then the decoder quality reconstructed image data. But if the number of versions be lost when they cross through of channel; so decoder reconstructs the data with the less quality (Kamnoonwatana et al., 2012). We have 15 scenario to receive copies and reconstruct the image at the receiver, Decoder 1234 for example, indicates that all four versions 1,2,3,4 have been received and Decoder 124 indicates that three versions 1, 2 and 4 have been received and Decoder 34 indicates that both versions 3 and 4 have been received and Decoder1 indicates that only one copy is received.

720

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

Figure 6. The structure of four versions coding system based DCT

Parallel links awgn channel For gain greater capacity, we made 4 links AWGN channel with several SNR and every of the sub images sent on a link. In this state, more data can be sent from channels. Lieu transferring all the images from a channel they are sent separately in the links. This will enhance the capacity of the channel. For an AWGN channel discrete - time with input power P and variance ϭ2, the capacity in terms of bits in per transfer is given by the following equation (Prookis et al., 1998). 1  p  C  log1  2  2    (5) After processing to measure the quality of the reconstructed image should be calculated PSNR. It can be utilized by following equations: MSE 





2 1  I 1 m , n   I 2  m , n  M *N M,N

PSNR  10 log10

(6)

2552

MSE (7) The levels of gray is 256; M, N are number of the rows and columns of image, MSE represents the mean squared error between the reconstruct and the original image, I1 is the original image I2 is the reconstructed image. Where the value of MSE is less, the error is low and the amount of PSNR will be high. Discrete cosine transform (DCT) expresses for image with below equation (Gonzalez et al., 2008).

c u ,v    u   v 

N 1 N 1

 f

x 0 y 0

   2x  1 u     2 y  1v  cos  2N 2N   

 x , y  cos 

  

(8)

where

721

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

    u ,  v     

1 n

u0

2 n

u  1,2,..., n  1

(9)

SIMULATIONS RESULTS Block diagram of proffered system is shown in Figure (7). First, Cameraman image is read with dimensions 256 × 256. In next block (MDC), the subsampling is performed and the dimensions of versions are become 128 × 128. Then these copies are got DCT transform and they are quantized. In the next block, we use an arithmetic code that it is a source coding and in the next block, we utilize convolutional code for channel coding and next, we do the spreading of signals with direct sequence (DS) technique. After that we use PAM modulation. Next block is four link AWGN channel with SNR=10, 12, 14, 16 dB. The next blocks do the works reverse in the transmitter such as demodulation, dispreading, channel decoding, source decoding, applying IDCT to the Signals and finally, with combining sub images with dimensions 128 × 128 is obtained original image with dimensions 256 × 256. With assumptions: bit/symbol=6, (length of Spreading Sequence)N=100000 ،(frequency sampling) fc=1000e5, (average pulse repetition time)Ts=50*10^-9, length of period pulse 0.7 ns, wide palse parameter 0.2877 ns, time period frame is 100 ns; received Versions in the receiver is shown in Figure (8).

Figure 7. Block diagram of proffer system LINK-UWB

a b

c

d

Figure 8. Sub images obtained in receiver

722

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

In Figure(9) is shown reconstructed image of the 4 versions of 128 × 128 with dimension 256 × 256.

Figure 9. Image after composition of the sub image DS-PAM

In Table 1 is shown average PSNR values for different lost versions by using multiple description coding. In cases when a prescription is lost, by obtained versions and averaging from the pixels, can be obtained approximation copies of lost. Table 1. PSNR to the state of lost prescriptions PSNR Number of copies lost 0 1 2 3

SNR= 2,3,4,5dB 21.9307 21.7833 21.5698 21.1043

SNR= 10.12.14.16 dB 22.2457 22.0311 21.7807 21.3482

In Table 2 is presented PSNR of received Images of DS-PAM UWB system with MDC, AWGN channel, SNR=10, 12, 14, 16 dB that each other is for a channel. PSNR of reconstructed image is investigated based on the number of lost copies, for state that only dc coefficient of original version has been received. Table 2. PSNR DC coefficient images Number of copies lost 0 1 2 3

PSNR SNR=10,12,14,16 19.7421 19.6470 19.5134 19.3807

It is observed that the PSNR of sent images by 3 coefficients of dc and ac are better than the PSNR of sent images only one coefficients of dc. Figure(10) shows PSNR values for the number of copies that have been lost.

Figure 10. Mean values of PSNR (dB) for different versions of the lost

723

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

Figure(11) and Table 3 show the simulation results without using MDC (SDC). In this method, there is possibility losing of image. MDC method gives high quality of image in against lost versions than the SDC method, with consideration main coefficients of DCT. In this state, SNR is considered 10, 12, 14, 16 dB for each channel In Figure(13) is drawn the ratio of SNR of AWGN channel to BER (error rate) of 12 signals of obtained before modulate and after Demodulate. .

Figure 11. Obtained image without MDC Table 3. PSNR image without MDC image image cameraman without MDC

PSNR 25.4000

Figure (12) PSNR to SNR ratio with MDC is shown for the restored image to the dimensions of 256 × 256.

Figure 12. PSNR to SNR ratio from MDC method with DCT

724

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

Figure 13. Error rates after Demodulate

The error rate before of the channel coding and after the channel decoded are shown for 12 signal that all set to zero. Therefore, the channel code is used to correct all errors. For another state received image of the DS-PAM UWB system using the MDC with dimensions 32 × 32, AWGN channel, SNR = 10,12,14,16 dB, and raised the Spread factor of signals. The results can be seen in Figures(14) and (15). Due to the large is image size, the image size have been got 32 × 32. In this case, the PSNR is 19.5713.

Figure 14.Origonal image 32 × 32

Figure 15. Image obtained 32 × 32

CONCLUSION In this paper, we have inspected the performance of DS-UWB systems with PAM modulation in AWGN channels after introduction of ultra-broadband systems, and at continuance multiple descriptions coding of the image are told. Finally, Parallel links AWGN system is investigated. Image transmission by Spreading, different Snrs, modes MDC, SDC with number of selected coefficients of prescriptions is investigated. It was observed that in low SNR, PSNR not change much, and channel code fulfill work better against noise. Several scenarios MDC Decoding were examined and it showed that the proposed system for image transmission has robustness against missed versions. REFRENCES Bai Z, Kwak K. 2005. ”Performance Analysis of Multiuser DS-PAM and TH-PPM UWB Systems in Data and ImageTransmission”, IEEE International Symposium onCommunications and Information Technology, vol. 2, pp. 851-854. diBenedetto MG, Kaiser T. 2006."UWB Communications Systems: A Comprehensive Overview", Cairo, Egypt: Hindawi, Emami S., 2013."UWB Communication Systems: Conventional and 60 GHz", Springer New York, ISBN: 978-1-4614-6752-6 (Print) 978-1-46146753-3 (Online). Franchi N, Fumagalli M, Lancini R, Tubaro S, 2005. "Multiple Description Video coding for scableand robust transmission over IP", IEEE Trans. Circuits and Syst. Video Technol. Vol.15, no. 3, pp. 321-334. Gezici S, Kobayashi H. 2005."Performance evaluation of impulse radio UWB systems with pulse-based polarity randomization", IEEE Trans. Signal Process., vol. 53, pp. 2537–2549. Ghavami M, Michael LB. 2004. "Ultra Wideband Signals and Systems in Communication Engineering", New York: Wiley. Gonzalez RC, Woods RE. 2008. “Digital Image Processing” Prentice Hall, Upper Saddle River, NJ, pp. 589 – 591. Kamnoonwatana N, Agrafiotis D, Canagarajah CN. 2012, "Flexible Adaptive Multiple Description Coding for Video Transmission", IEEE Trans. Circuits, Syst., Video Technol, vol. 22, Issue.1, pp. 1-11. Kshetrimayum RS, Guwahati GIIT. 2009. "An introduction to UWB communication systems", Potentials, IEEE, vol. 28, Issue. 2,pp. 9-13.

725

Intl. Res. J. Appl. Basic. Sci. Vol., 8 (6), 717-726, 2014

Lin C, Pan JS, Chen TY, Huang KC. 2007. “a covert communication scheme for a DCT based image multiple description coding system”, conference on Intelligent Information Hiding and Multimedia Signal Processing, Vol. 1, Issue. 26-28, pp. 395 – 398. Lv T, Zhang H. 2010.”A Selective Approach to Improve the Performance of UWB Image Transmission System over Indoor Fading Channels”,6th International Conference onWireless Communications Networking and Mobile Computing (WiCOM), pp. 1-4. Okiljevic P, Pokrajac IP, Vucic D. 2011. "Cyclic spectral analisys of UWB impulse radio signals with DS-PAM", IEEE Conf. Telecommunications Forum (TELFOR), 19th, pp. 790-793. Prookis J, Salehi M. 1998. "Contemporary Communication system using MATLAB, 1th Ed .Boston: PWS Publishing Company, pp. 345. 21 Qiu RC, Liu H Shen X. 2005."Ultra-wideband for multiple access communications," IEEE Commun. Mag., vol. 43, pp. 80–87. Somayazulu VS. 2002. "Multipleaccess performance in UWB systems using time hopping vs. direct sequence spreading", in Proc. IEEE Wireless Communications and Networking Conf., vol. 2, pp. 522-525. Vaishampayan V. 1993. “Design of multiple description scalar quantizers,” IEEE Trans. Inform. Theory, vol. 39, Issue. 3, pp. 821–834. 17 Wang Y, Reibman AR, Lin S. 2005. “Multiple description coding for video delivery,”, Proceedings of the IEEE, vol. 93, Issue. 1, pp.57-70. Win MZ, Scholtz RA. 2000."Ultra-wide bandwidth time-hoppingspread-spectrum impulse radio for wireless multiple-accesscommunications", IEEE Trans. Commun., vol. 48, no. 4, pp. 679-690. Xu Q, Stankovic V, Xiong Z. 2006. “Layered Wyner–Ziv video coding for transmission over unreliable channels”, Signal Processing, vol. 86, pp. 3212-3225. Yang L, Giannakis GB. 2004. "Ultra-wideband communications An idea whose time has come", IEEE Signal Process. Mag., vol. 21, pp. 26- 54. Zhang W, Bai Z, Xu S, Liu W, Kwak K. 2005. ”On the Performance of Multiple Access DS-BPAM UWB Systems in Data and ImageTransmission”, IEEE International Symposium on Communications and Information Technology, Vol. 2, pp. 851-854.

726