scholarly journals Design and implementation of a code-phase-shift keying spread spectrum receiver employing a FPGA baseband decoder

2002 ◽  
Author(s):  
S.K.S. Chan ◽  
V.C.M. Leung
Keyword(s):  
Phase Shift ◽  
Spread Spectrum ◽  
Phase Shift Keying ◽  
Design And Implementation ◽  
Shift Keying

Orthogonal Complex Quadrature Phase Shift Keying (OCQPSK) Spreading for 3G W-CDMA Systems

2011 ◽  
pp. 158-172
Author(s):  
S. Mishra
Keyword(s):  
Phase Shift ◽  
Spread Spectrum ◽  
Communication Systems ◽  
Multiple Channels ◽  
Phase Shift Keying ◽  
Reverse Link ◽  
Quadrature Phase Shift Keying ◽  
Quadrature Phase ◽  
Shift Keying ◽  
Spread Spectrum Systems

A variety of digital modulation techniques are currently being used in wireless communication systems. In 3G (third generation) spread-spectrum systems, such as W-CDMA (3GPP) and cdma2000 (3GPP2), the handset can transmit multiple channels at different amplitude levels. Modulation schemes such as OQPSK or GMSK do not prevent zero-crossings for multiple channels and are no longer suitable. There is a need for a modulation format or a spreading technique that can accommodate multiple channels at different power levels while producing signals with low peak-to-average power ratios. OCQPSK (Orthogonal Complex Quadrature Phase Shift Keying) has been proposed as the spreading technique for W-CDMA and cdma2000. OCQPSK is a complex spreading scheme that is very different from the modulation formats commonly used until now. The objective of this Chapter is to provide an overview of OCQPSK and explain how to start making modulation quality measurements on the reverse link (uplink) of 3G spread-spectrum systems. This chapter starts with the basic structure of the reverse link (uplink) for W-CDMA and cdma2000 with no scrambling, and explains the transition through complex scrambling to OCQPSK. The block diagrams shown are generic block diagrams for OCQPSK that are not particular to either W-CDMA or cdma2000. The chapter then describes: (1) why complex scrambling is used and how it works, and (2) why OCQPSK is used and how it works. Finally, this chapter provides how to measure modulation quality on the reverse link of 3G systems and a complete downlink physical layer model showing various results of BER and BLER calculation and also various time scopes and power spectrums.

scholarly journals An Unbalanced QPSK-Based Integrated Communication-Ranging System for Distributed Spacecraft Networking

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5803
Author(s):  
Na Zhao ◽  
Qing Chang ◽  
Hao Wang ◽  
Zhibo Zhang
Keyword(s):  
Phase Shift ◽  
Spread Spectrum ◽  
Power Distribution ◽  
Satellite System ◽  
Data Rate ◽  
Phase Shift Keying ◽  
Distribution Factor ◽  
High Data ◽  
Shift Keying ◽  
Integrated Communication

The spacecraft tracking telemetering and command (TT&C) system plays an essential role in celestial and terrestrial networks, requiring relative ranging and communication, particularly in satellite formation flying networks and distributed spacecraft networks. To achieve precious ranging and high-data-rate communication in a Master/Slave satellite architecture, an integrated communication-ranging system (ICRS) is introduced. ICRS is based on the inter-satellite spread spectrum ranging and spread/non-spread spectrum communication modulated by unbalanced quadrature phase shift keying (UQPSK). In both uplink and downlink, the in-phase (I) branches and the quadrature (Q) branches undertake the tasks of ranging and communication, respectively. In addition, a global navigation satellite system (GNSS) like signal is adopted in I branches for the sake of better ranging accuracy, and binary phase shift keying (BPSK) modulation is employed in Q branches for a higher data rate. Therefore, the key point of the ICRS design is the power resource allocation between two branches via the selection of a suitable power distribution factor (PWDF). Simulation results demonstrate the good performance of the proposed approach in ranging error and bit error rate (BER). In addition, a reasonable PWDF is recommended. Furthermore, the influence of clock offset is also taken into consideration.

scholarly journals Reception of differential binary phase shift keying signals with weight processing of sub-symbols in information transmission systems with frequency hopping spread spectrum.

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
A.A. Paramonov ◽  
◽  
Van Zung Hoang ◽  
Keyword(s):  
Phase Shift ◽  
Spread Spectrum ◽  
Noise Immunity ◽  
Frequency Hopping ◽  
Phase Shift Keying ◽  
Radio Communication ◽  
Frequency Hopping Spread Spectrum ◽  
Shift Keying ◽  
Radio Communication System ◽  
Binary Phase Shift Keying

Signals with frequency hopping spread spectrum (FHSS) have long been widely used in military radio communication systems (RCS) due to their frequency-energy characteristics. In such systems, the most important characteristic is noise immunity, i.e. the ability to ensure reliable transmission and reception of information under the influence of various types of organized intentional and unintentional interference. In this paper, we consider the case when the input of the receiver, in addition to the receiver's own noise, contains deliberate interference, which is considered noise interference. In this case, it is assumed that the interference covers only part of the operating frequencies of the radio communication system. The algorithm of optimal noncoherent signal reception with weight processing for making a decision about the transmitted symbol (bit) is in the focus of the paper. Static radio engineering methods, as well as Monte Carlo simulation, have been used to evaluate the noise immunity of receiving differential binary phase shift keying signals with FHSS when exposed to deliberate Partial-Band Interference. It is shown that the noise immunity of a radio communication system under conditions of destructive influence can be improved by using the intra-symbols FHSS mode with the proposed reception algorithm. With an increase in the signal-to-interference ratio, the noise immunity of information transmission increases significantly. The optimal strategy for dealing with Partial-Band Interference when the RCS is operating in the intra-symbols FHSS mode is to select the optimal multiplicity of symbol frequency diversity, which minimizes the probability of a bit error probability. The obtained dependencies are presented in order to compare and determine the effectiveness of the considered transmission mode with the proposed reception algorithm.

Design and Implementation of a Simple PSK/DPSK Modem

1987 ◽  
Vol 24 (3) ◽  
pp. 215-225 ◽  
Author(s):  
K. Warburton ◽  
R. A. Carrasco
Keyword(s):  
Phase Shift ◽  
System Performance ◽  
Phase Shift Keying ◽  
Design And Implementation ◽  
Shift Keying

The paper outlines the principles of phase shift keying and discusses, in detail, the implementation of a practical modem. The paper concludes by theoretically and practically evaluating the system performance.

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