New Wavelet Based Performance Analysis and Optimization of Scalable Joint Source/Channel Coder (SJSCC & SJSCCN) for Time-Varying Channels.

Transcription

1 Internatonal Research Journal of Engneerng and Technology (IRJET) e-issn: Volume: 02 Issue: 09 DEC-205 p-issn: New Wavelet Based Performance Analyss and Optmzaton of Scalable Jont Source/Channel Coder ( & N) for Tme-Varyng Channels. Dr. A.C.Bhagal, Mr.D.S.Bhangar2, Mr.K.G.JAmkhande3 Proffessor,Electroncs & Telecommuncaton Engg., ATS s SBGI Mraj, Maharashtra, Inda Asst. Prof.,Electroncs & Telecommuncaton Engg., ATS s SBGI Mraj, Maharashtra, Inda 3 Asst. Prof., Electroncs & Telecommuncaton Engg., ATS s SBGI Mraj, Maharashtra, Inda *** Abstract - In ths paper, we propose the model of Scalable Jont Source/Channel Codng wth new mother wavelet wth reduced hgh frequency frngng magntudes both at leadng and tralng edges(n) for wreless data transmsson where channel s nherently tme varyng and subject to Raylegh fadng nature. We consder the problem of stll mage data transmsson over tme varyng channels wth two Channel State Informaton (CSI) and three bt rates (, ½ and ¼) for the transmsson of data. We analyze the effect of CSI avalablty on the optmal performance analyss of proposed scheme. Our source model s based on two level wavelet mage decomposton usng Haar mother wavelet wth Set Partton In Herarchcal Tree (SPIHT) for sgnfcant coeffcents by dynamc threshold and channel codng s wth Rate-Compatble Punctured Convoluton (RCPC) Codes. We descrbe the new scheme of and ts optmzed performance for wreless channels. Fnally, we show how our optmzed scheme out performs over Optmzed Jont Source/Channel Coder () for channel states as well for varous bt rates [2][3]. In our optmzaton of Scheme, margnal mprovement n PSNR of 0.4dB s obtaned for both average and worst channels and sgnfcant mprovements of PSNR values n the order of 2dB s also obtaned for all three bt rates over exstng system. the PSNR values are mproved for all the btrates usng new mother wavelet compared to SJCC and. Key Words: N, wavelet, spht, cs, ojscc and sjscc. INTRODUCTION The feld of communcatons has developed snce past 60 years based on the separaton prncple. Separaton prncple states that the source codng and channel codng performed ndependently. The block dagram of separaton prncple s shown n Fg.. The separaton approach s to 205, IRJET dvde a sngle. Complex problem n to two smpler problems of desgnng source codng and channel codng ndependently. Ths approach of dvde and conquer prncple has led many advancements n the desgn of source codng and channel codng separately and was popular for tme-nherent channels. In 948, Shannon desgned and developed only source codng concepts for tme-nvarant channels wthout consderng channel codng constrants. Modern communcaton systems need heterogeneous desgn and development of Jont/Source channel codng for tme-varyng channels Vz. wreless moble communcaton and nternet access. The performance mprovement for moble and nternet access s acheved through jont source/channel codng over conventonal Separaton prncple desgn. Thus, the advance theory s essental for characterzng the Jont Source/Channel codng and performance analyss through optmzaton of communcaton systems[5][6][7]. Fg..: Separaton 2. APPLICATION AREAS. A modern communcaton system n whch source coder and channel coders are desgned n a dependent fashon and operates n cooperatve optmzaton of communcaton system components s referred as Jont Source/Channel Coder (JSCC). Advantages of JSCC are as follows Better performance s acheved for the systems wth crtcal resource constrants vz. rate of data transmsson, complexty, power and delay. Potental performance s acheved for hgh multuser systems and shared channels vz. wreless systems and nternet data. ISO 900:2008 Certfed Journal Page 989

2 Internatonal Research Journal of Engneerng and Technology (IRJET) e-issn: Volume: 02 Issue: 09 DEC p-issn: Sgnfcant performance s acheved for multuser systems wth heterogeneous source, channel and topologes. Source heterogenety: Dfferent data types travelng a sngle communcaton system have dfferent senstvtes to loss, corrupton of data and delay. Channel heterogenety: Dfferent channels wthn sngle network may have dfferent nose characterstcs, rates, packet sze, delay etc. Topology heterogenety: Some networks can be used smultaneously for pont-to-pont, broadcast and multple access communcaton systems. Sgnfcant gans are obtaned for the applcatons characterzed by unknown or tme-varyng sources, channels or networks. 3. SPIHT It s explaned that an alternatve prncple of operaton the prevous algorthm lke EZW algorthm to better understand the reasons for ts excellent performance. Accordng to SPIHT, partal orderng by magntude of the transformed coeffcent wth a set parttonng sortng algorthm, ordered bt plane transmsson of refnement bts, and explanaton of self smlarty of the mage wavelet transform across dfferent scales of and mage are the three concepts. In addton, A new and more effectve mplementatons of the modfed algorthm based on SPIHT [] t s explaned that scheme for progressve transmsson of the coeffcent values that ncorporates the concepts of orderng the coeffcents by magntude and transmttng the most sgnfcant bts frst. There s used unform scalar quantzer and clam orderng nformaton made ths smple quantzaton method more effcent than expected. An effcent way to code the orderng nformaton s also proposed accordng to above, result from the SPIHT codng algorthm n most uses surpass those obtaned from prevous algorthm. One mportant fact used n the desgn of the sortng algorthm s that we do not need to sort all coeffcents actually, we need an algorthm that smply select the coeffcents such than 2 n C,j < 2 n+ wth n decremented n each pass. Gven n, f C,j 2 n then we say that a coeffcent s sgnfcant; otherwse s called n sgnfcant To make clear relatonshp between magntude comparsons and message bts, we can be use the functon S n(p) = Max (C,j) 2 n 0 Otherwse To ndcate the sgnfcance of a set of coordnates P. smply the notaton of sngle coeffcent sets Sn(,j). Step : calculate the n to select the threshold level :n = log 2 (max(,j) (C,j) ) Step 2: for sortng purpose; followed by the pxel coordnates m(k) and sgn each of the coeffcents such that 2 n Cm (k) < 2 n+ (Sortng Pass) Step 3: output the n th most sgnfcant bt of all the coeffcents wth C,j 2 n+ f requred, those that had ther coordnate transmtted n prevous sortng passes Step 4 : Decrement n by one and to go to step 2. The above steps that can be mplemented and stop at the desred the rate or dstorton normally, good qualty mages can be recovered after a relatvely small amount of the coeffcents are transmtted. In a practcal mplementaton purpose the sgnfcance nformaton s stored n three-ordered lst as. ) LIS: Lst of nsgnfcant set contans sets of dscrete cosne transform coeffcents whch are defned by tree structures [6][8] and whch had been found have magntude smaller than the threshold (nsgnfcant) 205, IRJET ISO 900:2008 Certfed Journal Page 990 ) ) LIP: Lst of nsgnfcant pxels contans ndvdual coeffcents that have magntude smaller than the threshold. LSP: Lst of sgnfcant pxels found to have magntude larger that the threshold (sgnfcant accordng to above tree ordered we can be performed for codng purpose for 8х8 block of mage whch s transformed by DCT [7] (Dscrete cosne transform). Accordng to SPIHT, the compresson takes place manly because after the transformaton most of the energy of the mage s concentrated n low frequency coeffcents that s DC coeffcents and rest of the coeffcents have very low values [3]. Ths means that there are many zeros n the most sgnfcant bt planes of the coeffcents, untl the frst sgnfcant bt of a certan coeffcent s found, t contans more nformaton. If largest magntude coeffcent s there, then we get frst non-zero bt. For each coeffcent we call ts frst one bt (non-zero bt) startng from most sgnfcant to less sgnfcant bts (MSB to LSB) as the frst sgnfcant bt (FSB). And the bts of coeffcents pror to the frst sgnfcant bt wll be referred to as the zero bt (ZBS). The sgn nformaton s represented by the sgn bt (SB), whle the rest of the bts after the frst sgnfcant bts are called row bts (RBS). Accordngto above defntons,

3 Internatonal Research Journal of Engneerng and Technology (IRJET) e-issn: Volume: 02 Issue: 09 DEC p-issn: codng startng wth bt plane. In each bt plane the codng wll be form the lowest frequency coeffcent (DC coeffcents) to hghest frequency coeffcents (AC coeffcents).spiht encoder uses these prncples to progressvely transmt DCT (Dscrete cosne transform) coeffcents startng wth the most mportant nformaton. The coeffcents are sorted and the sortng nformaton s contaned n set of elements m (k) contans the (,j) coordnates of a coeffcent (C,j) and such that Cm(k) Cm(k+) for all values of k.[6] The frst coeffcent Cm () =C(2,3) s s00. The second coeffcent Cm (2) = C (3,4) s s00.and so on. The sortng nformaton that the encoder has to transmt s the sequence m (k) or (2, 3) (3, 4).. In addton. It has to transmt the 8 sgns and 6 coeffcents n order of sgnfcant bts. A drect transmsson would send the 6 numbers. SSSSSS..SS, ;but ths clearly wasteful. Instead of that, t can be performed by technque for teraton a sortng purpose. In the frst teraton t transmts the two coeffcents (whose MSB s one) as shown n fgure, number of coeffcents C,j n fgure2 that satsfy 2 7 C,j 2 8 followed by two pars of coordnates (2,3) and (3,4) accordng to our fgure. And by the sgns of the frst two coeffcents. Coeffcents C23 and C3,4 are constructed as 8 bt numbers s But t can be recover by transmttng MSB and remanng 4 coeffcents are constructed as all zero. The most sgnfcant bts of the largest coeffcents are transmtted frst accordng to dynamc thresholdng [6]. D N 0 S E S, m m j0 A P () Where, N s the number of subbands, S s the total number of pxels n the orgnal mage, S s the number of pxels n the th subband, E,m, s the dstorton caused by m bt quantzaton for the th subband and A, P are bt error senstvty and channel bt error rate after channel codng for the jth bt of the th subband. The graphcal representaton of general rate dstorton (R- D) functon of Jont Source/Channel Coder s as shown n Fg.4.. Fg. 4.: Graphcal representaton of Jont Source/Channel 5. RESULTS. Results obtaned by our Scalable Jont Source/Channel Coder are shown n Table- for two channel states and three BERs. JSCC BER x WORKING OF THE SYSTEM. SCHEME Avg worst avg worst avg worst The proposed scheme of Jont Source/Channel Codng s developed for transmttng data and mage streams over wreless Raylegh channel. The channel state s estmated and optmum bts are allocated to quantzer and channel coder jontly for mprovement n PSNR and better vsual qualty of reconstructon of mages. The trade-off between source codng rate and channel codng s acheved through Jont Source/Channel Rate-Dstorton functon. The data stream s decorrelated through multlevel and multresoluton dscrete wavelet transform (DWT) usng Haar and Daubeches mother wavelets. Each subband s reshaped to Gaussan dstrbuton by sutable flter. Each sample of subband s then quantzed wth Lloyd max nonlnear quantzer. The output of quantzer s then protected through unequal protecton by channel coder. The recever performs exactly nverse process as per the channel states used for transmsson. The rate dstorton (R-D) functon for memoryless channel s expressed n equaton no-. (PSNR) Table-: Result of BER Vs PSNR over Graphcal representaton as shown n fg 5. are results of and wll be clearly ndcatng margnal mprovement by over other optmzed JSCC Schemes for wreless channels. Over other optmzed JSCC Schemes for wreless channels. Fg 5.: Result of BER Vs PSNR over. 205, IRJET ISO 900:2008 Certfed Journal Page 99

4 Internatonal Research Journal of Engneerng and Technology (IRJET) e-issn: Volume: 02 Issue: 09 DEC-205 p-issn: Rate Schmes BER X Fgure 6.4 : Graphcal representaton of PSNR Vs channel states for N schemes Table-2: Result of over for varous Bt Bt rate PSNR Vs BER PSNR 6. CONCLUSIONS Bt rate 0.5 Bt rate 0.25 BER Fg. 5.2: Result of over for varous Bt Rates over other optmzed JSCC Schemes for wreless channels. Results of N over other JSCC schemes Results of New are gven n table (6.) for varous BERs and two channel states. Results obtaned are comparable to and schemes. Graphcal representatons of results are shown n fgure 6.4. Table (6.) : PSNR n db for New Vs BERs Schem es BER REFERENCES [] Hugenauer, Source-Controlled Channel Decodng. IEEE Transacton Communcaton. Vol. 43, pp , Sept [2] J. W. Modestno and D.G.Daut, Combned Source/Channel Codng of Images. IEEE Transacton Communcaton. Vol. COMM-27, pp , Nov [3] M. J. Ruf., Combned Source/Channel Codng for Image Transmsson. In Proc. 6th Jont Conference Communcaton and Codng, Selva, Italy, March 994. [4] G. Cheung and A. Zakhor, Jont Source/Channel Codng of Scalable Vdeo Over Nosy Channels. In Proc. Int. Conf. Image Processng, Lausanne, Swtzerland, Vol.3, pp , Sept x0-2 (PSNR n db) WORST WORS T WORST New New(2 L) , IRJET We have modeled the Scalable Jont Source/Channel Coder () and analyzed wth new mother wavelet wth reduced hgh frequency frngng magntudes both at leadng and tralng edges for wreless channels and extensve smulatons are carred out for two channel states. The results obtaned are margnally mproved wth RCPC Channel Coder over exstng Optmzed Jon Source/Channel Coder (). Overall mprovement of PSNR n the order of 0.4dB s notced n our developed model of for two channel states and three BER values. Further, the proposed system performance can also be analyzed for the wder range of BERs. Results obtaned for three bt rates, 0.5 and 0.25 by the proposed Scalable Jont Source/Channel Coder s shown n Table-2 for varous BER values. Fnally the PSNR values are mproved for all the btrates usng new mother wavelet. ISO 900:2008 Certfed Journal Page 992

5 Internatonal Research Journal of Engneerng and Technology (IRJET) e-issn: Volume: 02 Issue: 09 DEC p-issn: [5] M. Srnvasan and R. Chellappa, Jont Source/Channel Codng of Images. In Proc. IEEE Conf. On Acc. & Speech Sgnal Processng, Munch, ermony, 997. [6] Jll R. Boldschneder and Eve A. Rskn, Jont Optmal Bt Allocaton and Best Bass Selecton for Wavelet Packet Trees. Proc. Of IEEE Int. Conf., pp , June [7] Srnvasan, Chellappa and Vurlna, Adaptve Source/Channel Subband Vdeo Codng for Wreless Channels. IEEE Sgnal Processng Socety Workshop on Multmeda Sgnal Processng, pp - 4, June , 997. [8] A. C. Bhagal Dgtal Sgnal Processng wth MATLAB Programs 3Ed. Chapter-3. [9] H. Jafarkhan, P. Lgdas, and N. Rarvardn, Adaptver rate allocaton n a Jont Source/Channel Codng framework for wreless channel. In IEEE Trans. On Vehcular Technology, [ [0] G. Sherwood and K. Zeger, Progressve mage codng for nosy channels. IEEE Sgnal Processng Lett. Vol. 4, pp 89-9, July. 997Sept , IRJET ISO 900:2008 Certfed Journal Page 993