Efficient Receiver Implementation for Mobile Applications

2009 ◽  
pp. 271-298
Author(s):  
Costas Chaikalis ◽  
Felip Riera-Palou
Keyword(s):  
Communication Systems ◽  
Low Complexity ◽  
Wireless Communication Systems ◽  
Channel Decoding ◽  
High Data ◽  
Data Rates ◽  
Channel Effects ◽  
Environment Simulation ◽  
Very High

Modern and future wireless communication systems such as UMTS and beyond 3G systems (B3G) are expected to support very high data rates to/from mobile users. This poses important challenges on the handset design as they should be able to attain an acceptable operating bit error rate (BER) while employing a limited set of resources (i.e. low complexity, low power) and often, with tight processing delay constraints. In this chapter we study how channel decoding and equalisation, two widely used mechanisms to combat the deleterious channel effects, can be made adaptable in accordance to the instantaneous operating environment. Simulation results are given demonstrating how receiver reconfigurability is a promising method to achieve complexity/delay efficient receivers while maintaining prescribed quality of service (QoS) constraints.

scholarly journals Underwater Optical Wireless Communications with Chromatic Dispersion and Time Jitter

Computation ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 35 ◽  
Author(s):  
Roumelas ◽  
Nistazakis ◽  
Stassinakis ◽  
Volos ◽  
Tsigopoulos
Keyword(s):  
Wireless Communications ◽  
Communication Systems ◽  
Chromatic Dispersion ◽  
Mathematical Expression ◽  
Optical Wireless ◽  
Optical Wireless Communications ◽  
Time Jitter ◽  
High Data ◽  
Data Rates ◽  
Very High

The obsolete communication systems used in the underwater environment necessitates the development and use of modern telecommunications technologies. One such technology is the optical wireless communications, which can provide very high data rates, almost infinite bandwidth and very high transmission speed for real time fast and secure underwater links. However, the composition and the optical density of seawater hinder the communication between transmitter and receiver, while many significant effects strongly mitigate the underwater optical wireless communication (UOWC) systems’ performance. In this work, the influences of chromatic dispersion and time jitter are investigated. Chromatic dispersion causes the temporal broadening or narrowing of the pulse, while time jitter complicates the detection process at the receiver. Thus, the broadening of the optical pulse due to chromatic dispersion is studied and the influence of the initial chirp is examined. Moreover, the effect of the time jitter is also taken into consideration and for the first time, to the best of our knowledge, a mathematical expression for the probability of fade is extracted, taking into account the influence of both of the above-mentioned effects for a UOWC system. Finally, the appropriate numerical results are presented.

scholarly journals Precoded SLM and PTS Scheme for Reduced PAPR in OFDM for Wireless Communications

YMER Digital ◽  
2021 ◽  
Vol 20 (12) ◽  
pp. 856-866
Author(s):  
Malleswari Akurati ◽  
◽  
Satish Kumar Pentamsetty ◽  
Satya Prasad Kodati ◽  
◽  
...  
Keyword(s):  
Wireless Communication ◽  
Bit Error Rate ◽  
Error Rate ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Low Complexity ◽  
Wireless Communication Systems ◽  
High Data ◽  
High Power Amplifier

Orthogonal Frequency Division Multiplexing (OFDM) contribute high data rates in current as well as future wireless communication systems but it aches from high Peak to Average Power Ratio (PAPR). But this high PAPR makes the High-Power Amplifier (HPA) complex which increases the cost of it and leads to the drawbacks like Inter Carrier Interference (ICI) and rise in out of band radiation. Even though many techniques are there to decrease the complexity of HPA by reducing the PAPR, Selected Mapping (SLM) and the Partial Transmit Sequence (PTS) provides less PAPR with low complexity. In this paper, both PTS and SLM are combined with Discrete Sine Transform (DST) and their PAPR and efficiencies are also compared with OFDM signal. The proposed hybrid DST-PTS and DST-SLM provides less PAPR compared to OFDM, SLM and PTS techniques with low complexity. Also, the bit error rate for DST-SLM and DST-PTS techniques are compared for different values of SNR. In future wireless communication systems, these proposed techniques can be used as they provide less bit error rate and less PAPR with low complexity

scholarly journals Relay-assisted WDM-FSO System: A Better Solution for Communication under Rain and Haze Weather Conditions

2017 ◽  
Vol 4 ◽  
pp. 54-59
Author(s):  
Navneet Dayal ◽  
Preeti Singh ◽  
Pardeep Kaur
Keyword(s):  
Wavelength Division Multiplexing ◽  
Electromagnetic Interference ◽  
Communication Systems ◽  
Weather Conditions ◽  
Wireless Communication Systems ◽  
Wavelength Division ◽  
High Data ◽  
Space Optics ◽  
System A ◽  
Data Rates

Among various conventional wireless communication systems, Free Space Optics (FSO) may be distinguished as well, which provides a good level security, high data rates, an enormous bandwidth and negligible susceptibility to electromagnetic interference. The main problem arises with unfavorable weather conditions, which affect the system’s parameters and require an aversion to other paths. The weather conditions discussed are rain and haze. Elimination of their adverse effects is essential for establishing a better communication system. The routing path is a major issue, as its decreased parameters lead to the diversion of the transmitted signal or to its total loss. In this article, increased system path length and proficiency levels are demonstrated by using relays, which are assisted by Wavelength Division Multiplexing (WDM).

scholarly journals Propagation Channel Measurements in the mm- and Sub-mm Wave Range for Different Indoor Communication Scenarios

2021 ◽  
Vol 42 (4) ◽  
pp. 357-370
Author(s):  
M. A. Salhi ◽  
T. Kleine-Ostmann ◽  
T. Schrader
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Wireless Communication Systems ◽  
Electromagnetic Spectrum ◽  
Channel Measurements ◽  
Frequency Range ◽  
Propagation Channel ◽  
Data Rates ◽  
Indoor Wireless ◽  
Wave Range

AbstractIncreasing data rates in wireless communications are accompanied with the need for new unoccupied and unregulated bandwidth in the electromagnetic spectrum. Higher carrier frequencies in the lower THz frequency range might offer the solution for future indoor wireless communication systems with data rates of 100 Gbit/s and beyond that cannot be located elsewhere. In this review, we discuss propagation channel measurements in an extremely broad frequency range from 50 to 325 GHz in selected indoor communication scenarios including kiosk downloading, office room communication, living rooms, and typical industrial environments.

scholarly journals A low complexity digital frequency calibration with high jitter immunity for ultra-low-power oscillators

2019 ◽  
Vol 17 ◽  
pp. 145-150
Author(s):  
Markus Scholl ◽  
Ralf Wunderlich ◽  
Stefan Heinen
Keyword(s):  
Low Power ◽  
Communication Systems ◽  
Calibration Method ◽  
Low Complexity ◽  
Frequency Stability ◽  
Wireless Communication Systems ◽  
Ultra Low Power ◽  
Wireless Transceiver ◽  
Digital Frequency ◽  
Frequency Calibration

Abstract. This paper presents a highly efficient digital frequency calibration method for ultra-low-power oscillators in wireless communication systems. This calibration method locks the ultra-low-power oscillator's output frequency to the reference clock of the wireless transceiver during its send- and receive-state to achieve frequency stability over process variation and temperature drifts. The introduced calibration scheme offers high jitter immunity and short locking periods overcoming frequency calibration errors for typical ultra-low-power oscillator's by utilizing non-linear segmented feedback levels. In measurements the proposed calibration method improves the frequency stability of an ultra-low-power 32 kHz oscillator from 53 to 10 ppm ∘C−1 over a wide temperature range for temperature drifts of less than 1 ∘C s−1 with an estimated power consumption of 185 nW while coping with relocking periods of 7 ms.

scholarly journals Research of the Channel Estimation in Wireless Communication Systems

2019 ◽  
Vol 25 ◽  
pp. 01002 ◽  
Author(s):  
Lili Zhao ◽  
Peng Zhang ◽  
Qicai Dong ◽  
Xiangyang Huang ◽  
Jianhua Zhao ◽  
...  
Keyword(s):  
Wireless Communication ◽  
Channel Estimation ◽  
Communication Technology ◽  
Communication Systems ◽  
Communication Channel ◽  
Data Transfer ◽  
Estimation Methods ◽  
Wireless Communication Systems ◽  
Data Transfer Rate

Wireless communication technology has been developed rapidly after entering the 21st century. Data transfer rate increased significantly as well as the bandwidth became wider and wider from 2G to 4G in wireless communication systems. Channel estimation is an import part of any communication systems; its accuracy determines the quality of the whole communication. Channel estimation methods of typical wireless communication systems such as UWB, 2G and 3G have been researched.

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