Implementation of Wireless Receiver Algorithms

Implementation of Wireless Receiver Algorithms

Figure 1 System Specifications Tsimenidis 2016

Figure 2 Message format Tsimenidis 2016

Figure 3 Noncoherent receiver Tsimenidis 2016

Figure 4 Coherent receiver Tsimenidis 2016

Figure 5 Receiver FrontEnd Tsimenidis 2016

Figure 6 Frequency response of a passband filter Tsimenidis 2016

Figure 7 Bandpass filter response

Figure 8 Bandpass filter inputoutput

Figure 9 Implemented DPSK demodulator Tsimenidis 2016

Figure 10 Lowpass filter inputoutput

Figure 11 Optima sample time diagram

Figure 12 Symbol with 40 samples Tsimenidis 2016

Figure 13 EarlyLate sample at an arbitrary point Tsimenidis 2016

Figure 14 EarlyLate sample at the maximum point of power Tsimenidis 2016

Figure 15 EarlyLate symbol synchronization inputoutput

Figure 16 Result of noncoherent receiver detection

Figure 17 IQ Downconverter Tsimenidis 2016

Figure 18 Sine and cosine table graphs

Figure 19 Index control flow Tsimenidis 2016

Figure 20 Filter comparison Tsimenidis 2016

Figure 21 Downconversion x3I vs x3Q counter clockwise

Figure 22 Downconversion x4I vs x4Q counter clockwise

Figure 23 x6I vs x6Q

Figure 24 Averaging approach to overcome the jitter Tsimenidis 2016

Figure 25 Code to solve the jitter

Figure 26 Principle of the differential detector Tsimenidis 2016

Figure 27 Constellation without Phase Offset dI Vs dQ

Figure 28 Result of coherent receiver detection using differential coherent demodulator

Figure 29 BPSK and DPSK BER comparison Tsimenidis 2016

Figure 30 Costas Loop algorithm Tsimenidis 2016

Figure 31 Costas loop yQ vs yI

Figure 32 Message obtained using Costas loop

Figure 33 BER comparison of different modulation schemes and techniques Sklar 1983

This project is focused on implementing and coupling several functional blocks that will allow us to detect extract and decode a wireless message that is being broadcasted in the Merz lab of computers In the following sections we will find the implementations of coherent and noncoherent receivers

In the section 1 we define the basic background knowledge that will be commonly used in the posterior phases of the report We define the basic structure and features of the transmitter as well as the message format that the system is intended to detect Finally we define what is a coherent and a noncoherent system and provide a classification about the different techniques

In the section 2 we will analyse the noncoherent receiver implementation from the message acquisition going to the filter section signal scaling and refinement using a DPSK demodulator to define the probable symbols represented then establishing a synchronization for the symbol and finally presenting the message obtained

The section 3 will focus in the realization of a coherent receiver considering two possible variations on this type of implementation the first will be developed using a differential coherent demodulator in this technique we will not recover the carrier signal The second implementation of this receiver will be done using a carrier recovery technique which is in this case a Costas Loop Algorithm

Some common blocks are done in all the possible implementations that were carried out during this project the first is the receiver frontend which is the responsible to acquire and prepare the signal for the posterior processing To recover the symbol synchronization we use a technique called earlylate gate this will let us know what is the most convenient instant of the time to sample the signal For the case of coherent signal we must adapt this technique to apply it separately for the signal I inphase and Q quadrature

The section 4 contains analysis conclusions and discussions of the results obtained during the realization of the phases

The last sections of the report detail the references used for further explanations and the different programs used for implementing each block

In each section we include little further

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