Chapter 5 is devoted to the basic procedures performed in the radio path of the receiver and how to implement them, which increase the efficiency of signal reception. The main problem that must be solved in the receiving path is the optimal construction of a demodulator when some characteristics of the received signal are unknown or are known with some accuracy. In the absence of some information about the received signal, quasi-optimal reception using incoherent detectors is widely used. Such detectors are most widely used in analog signal receivers. The possibility of obtaining information about the frequency and phase of the received signal with high accuracy in digital systems makes it possible to apply coherent processing. This required not only the use of digital modulation in the transmitter but also the complexity of the radio signal generation algorithm based on the use of the properties of mutually orthogonal modulating sequences, which made it possible to implement optimal signal reception. The result of processing such signals in the optimal demodulator block is a set of correlation functions, which are a set of symbols that describe some part of the information digital sequence. This chapter discusses options for constructing an optimal demodulator, determined by the multiplexing method. An increase in the probability of correct reception of information symbols distorted in the radio channel by fading caused by multipath signals at the input of the receiver and other sources of electromagnetic radiation is achieved by using the detector to make a decision about each bit of information on the received group of symbols (Viterbi, Fano decoder). This chapter describes the solution search algorithms for each method. The use of the described methods for improving the efficiency of digital systems and the receiver, as an integral part of it, is impossible without the synchronous operation of the BS and MS, which are most exposed to external conditions, and at the same time, ensure the mobility of at least one of the terminal devices. The tool that provides the BS with signal generation for an individual subscriber (cell search) significantly increases the efficiency of the data transmission system, simplifies the interaction between the MS and the BS, and reduces the power consumption of the MS. This chapter describes the cell search process based on the synchronization system and correlation processing of reference signals.

Frequency Converters and Optimal Reception

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发表日期：

2026年

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Vasiliy V. Logvinov,
Sergey M. Smolskiy,
Iuliia K. Logvinova

摘要

Chapter 5 is devoted to the basic procedures performed in the radio path of the receiver and how to implement them, which increase the efficiency of signal reception. The main problem that must be solved in the receiving path is the optimal construction of a demodulator when some characteristics of the received signal are unknown or are known with some accuracy. In the absence of some information about the received signal, quasi-optimal reception using incoherent detectors is widely used. Such detectors are most widely used in analog signal receivers. The possibility of obtaining information about the frequency and phase of the received signal with high accuracy in digital systems makes it possible to apply coherent processing. This required not only the use of digital modulation in the transmitter but also the complexity of the radio signal generation algorithm based on the use of the properties of mutually orthogonal modulating sequences, which made it possible to implement optimal signal reception. The result of processing such signals in the optimal demodulator block is a set of correlation functions, which are a set of symbols that describe some part of the information digital sequence. This chapter discusses options for constructing an optimal demodulator, determined by the multiplexing method. An increase in the probability of correct reception of information symbols distorted in the radio channel by fading caused by multipath signals at the input of the receiver and other sources of electromagnetic radiation is achieved by using the detector to make a decision about each bit of information on the received group of symbols (Viterbi, Fano decoder). This chapter describes the solution search algorithms for each method. The use of the described methods for improving the efficiency of digital systems and the receiver, as an integral part of it, is impossible without the synchronous operation of the BS and MS, which are most exposed to external conditions, and at the same time, ensure the mobility of at least one of the terminal devices. The tool that provides the BS with signal generation for an individual subscriber (cell search) significantly increases the efficiency of the data transmission system, simplifies the interaction between the MS and the BS, and reduces the power consumption of the MS. This chapter describes the cell search process based on the synchronization system and correlation processing of reference signals.