modulation and coding course

... bandwidth constraint  Nyquist bandwidth constraint:  The theoretical minimum required system bandwidth to detect Rs [symbols/s] without ISI is Rs/2 [Hz].  Equivalently, a system with bandwidth ... filter Equalizing filter Threshold comparison For bandpass signals Compensation for channel induced ISI Baseband pulse (possibly distored) Sample (test statistic) Baseband pulse Received waveform Step 1 – ... [symbols/s] without ISI.  Bandwidth efficiency, R/W [bits/s/Hz] :  An important measure in DCs representing data throughput per hertz of bandwidth.  Showing how efficiently the bandwidth resources...

Ngày tải lên: 18/10/2013, 06:15

... ,zzZ ZZZZ = =Z Channel Lecture 10 2 Last time, we talked about:  Channel coding  Linear block codes  The error detection and correction capability  Encoding and decoding  Hamming codes  Cyclic codes Lecture 10 ... design and evaluation of the code.  Block codes are based on algebraic/combinatorial techniques.  Convolutional codes are based on construction techniques. Digital Communications I: Modulation and ... specified by three parameters or where  is the coding rate, determining the number of data bits per coded bit.  In practice, usually k=1 is chosen and we assume that from now on.  K is the constraint...

Ngày tải lên: 25/10/2013, 06:15

... error correction coding?  Error performance vs. bandwidth  Power vs. bandwidth  Data rate vs. bandwidth  Capacity vs. bandwidth (dB) / 0 NE b B P A F B D C E Uncoded Coded Coding gain: For ... codeword coset coset leaders kn i − = 2, ,3,2 n V i e th:i Digital Communications I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 9 Lecture 9 36 Cyclic block codes  Algebraic ... detection and correction codes Lecture 9 28 Linear block codes – cont’d  Standard array  For row , find a vector in of minimum weight which is not already listed in the array.  Call this pattern and...

Ngày tải lên: 25/10/2013, 06:15

... code uses two levels on coding, an inner code and an outer code (higher rate).  Popular concatenated codes: Convolutional codes with Viterbi decoding as the inner code and Reed-Solomon codes ... each state, and keeps only the path with the largest metric, called the survivor, together with its metric. Lecture 12 6 Soft and hard decision decoding …  ML soft-decisions decoding rule:  Choose ... the decoder with a measure of confidence for the decision. Digital Communications I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 12 ...

Ngày tải lên: 29/10/2013, 13:15

... levels.  Decoding based on soft-bits, is called the “soft-decision decoding”.  On AWGN channels, 2 dB and on fading channels 6 dB gain are obtained by using soft-decoding over hard-decoding. Lecture ... state 101 010 11 011 100 10 001 110 01 111 000 00 0 S 1 S 2 S 3 S 0 S 2 S 0 S 2 S 1 S 3 S 3 S 1 S 0 S 1 S 2 S 3 S 1/11 1/00 1/01 1/10 0/11 0/00 0/01 0/10 Input Output (Branch word) Modulation, Demodulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 11 ... level) which are called “hard- bits”.  Decoding based on hard-bits is called the “hard-decision decoding”. Lecture 11 23 Example of Hard decision Viterbi decoding-cont’d  i=3 0 2 0 1 2 1 0 1 1 0 1 2 2 1 0 2 1 1 1 6 t 1 t 2 t 3 t 4 t 5 t 1 0 2...

Ngày tải lên: 29/10/2013, 13:15

... 6 Scope of the course …  Learning fundamental issues in designing a digital communication system (DCS):  Utilized techniques  Formatting and source coding  Modulation (Baseband and bandpass signaling)  Channel ... User Lecture 1 25 Bandwidth of signal …  Different definition of bandwidth: a) Half-power bandwidth b) Noise equivalent bandwidth c) Null-to-null bandwidth a) Fractional power containment bandwidth b) ... ergodic in mean and autocorrelation, if and , respectively. Lecture 1 7 Practical information  Course material  Course text book:  “Digital communications: Fundamentals and Applications”...

Ngày tải lên: 08/11/2013, 18:15

... Quantization and encoding 3. Baseband transmission Lecture 2 10 Encoding (PCM)  A uniform linear quantizer is called Pulse Code Modulation (PCM).  Pulse code modulation (PCM): Encoding the quantized ... NRZ Lecture 2 21 M-ary pulse modulation  M-ary pulse modulations category:  M-ary pulse-amplitude modulation (PAM)  M-ary pulse-position modulation (PPM)  M-ary pulse-duration modulation (PDM)  M-ary ... variance: 2 Sat 2 Lin 222 )()(})]({[ σσσ +==−= ∫ ∞ ∞− dxxpxexqx q E ll L l l qxp q )( 12 2 12/ 0 2 2 Lin ∑ − = = σ Uniform q. 12 2 2 Lin q = σ Digital Communications I: Modulation and Coding Course Period 3 – 200/ Catharina Logothetis Lecture 2 Lecture 2 18 PCM waveforms  PCM...

Ngày tải lên: 08/11/2013, 18:15

... symbol Mi ,,1 K = M-ary modulation Lecture 3 13 Baseband and bandpass  Bandpass model of detection process is equivalent to baseband model because:  The received bandpass waveform is first ... Sampling  Aliasing  Quantization  Uniform and non-uniform  Baseband modulation  Binary pulse modulation  M-ary pulse modulation  M-PAM (M-ay Pulse amplitude modulation) Lecture 3 10 Example: Channel ... tr. and equal energy per tr. data bit for binary-PAM and 4-ary PAM: • 4-ary: T=2Tb and Binay: T=Tb • 4-ary PAM (rectangular pulse) Binary PAM (rectangular pulse) ‘11’ 22 10BA = Lecture 3 8 Demodulation...

Ngày tải lên: 27/01/2014, 08:20

... tTstrz i i −∗= ∗ Mi , ,1 = ), ,,())(), ,(),(( 2121 MM zzzTzTzTz = =z Digital Communications I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 4 Lecture 4 11 Signal space …  ... A 0 1 s 2 s T A T A− 0 0 Tt )( 1 t ψ T 1 0 0)()()()( )()()(),( /)(/)()( )( 122 0 1212 1111 0 2 2 11 =−−= −=>=< == == ∫ ∫ tAtstd Adtttstts AtsEtst AdttsE T T ψ ψψ ψ 1 2 Lecture 4 3 Receiver job  Demodulation and sampling:  Waveform recovery and preparing the received signal for detection:  Improving the signal ... filter Equalizing filter Threshold comparison For bandpass signals Compensation for channel induced ISI Baseband pulse (possibly distored) Sample (test statistic) Baseband pulse Received waveform Step 1 –...

Ngày tải lên: 27/01/2014, 08:20

... PAM )( 1 t ψ 0 2 s 3 s 5 2 b E 5 6 b E 5 6 b E − 5 2 b E − 4 s 1 s 4-ary PAM T t )( 1 t ψ T 1 0 Digital Communications I: Modulation and Coding Course Period 3 - 2007 Catharina Logothetis Lecture 5 Lecture 5 20 Eb/No figure of merit ... noise vector are i.i.d Gaussian random variables with zero-mean and variance . The noise vector pdf is  The elements of observed vector are independent Gaussian random variables. Its pdf is ), ... liesPr()( )(1)( icie mPmP − = i m i s z i Z sent) and ˆ Pr()( iiie mmmmP ≠ = Lecture 5 16 Union bound  Let denote that the observation vector is closer to the symbol vector than , when is transmitted.  depends only on and .  Applying...

Ngày tải lên: 27/01/2014, 08:20

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