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In this paper an analytical approach is presented to determine the impact of frequency offset, timing jitter and additive white Gaussian noise (AWGN) on the bit error rate (BER) performance of a multi-carrier direct-sequence code division multiple access (MC-DS-CDMA) system over a Rayleigh Fading Channel. The analysis developed the pdf (probability density function) at the receiver considering combined...
We evaluate the outage probability of cognitive amplify-and-forward relay networks with cooperation between certain secondary users chosen by multi-relay selection based on the underlay approach, while adhering to the interference constraint on the primary user. A max-min strategy is employed to perform best relay or multi-relay, i.e. between two and four relays, selection. We obtain analytical expressions...
Code-hopping multiple access (CHMA) has been an emerging multiple access technology designed to increase the number of users in Code-division multiple access (CDMA) systems. It was designed to overcome the limitations in the number of code word's required for communication in existing systems. However, it may experience degradation due to symbol perforation occurring due to code collisions when the...
In this paper, a turbo-coded optical interleave-division multiple-access (OIDMA) scheme is studied. A maximum a posteriori (MAP) based asynchronous on-off keying (OOK) MUD algorithm is proposed. Besides, system capacity is analyzed with an iterative technique called SNR evolution. BER is evaluated over log-normal turbulence channels, taking into consideration the effects of thermal noise and background...
In cognitive multimedia mesh networks (CMMNs), unlicensed users (secondary users, SUs) can share the spectrum with licensed users (primary users, PUs) on a non-interfering basis. The main challenge in CMMN is how to implement an efficient optimal control policy that can allocate spectrum and transmission powers for the SUs efficiently and how to adapt these resources to the changing network conditions...
Time varying channel breaks the orthogonality between the subcarriers of Orthogonal Frequency Domain Multiplexing (OFDM). This introduces Intercarrier Interference (ICI). One of the ways to mitigate ICI is to first estimate the channel and then equalize it. In this paper we propose to estimate the channel using Discrete Proplate Spheroidal Sequences (DPS) using pilot carriers interleaved with data...
Non-coherent UWB receivers are often implemented using energy detection architectures which are very sensitive to noise in the channel and interference. Therefore, the receiver bandwidth plays an important role since the total noise and interference energy is proportional to this bandwidth. This work provides analytical expressions to find the optimal receiver bandwidth and quantifying the effect...
The conventional amplify-and-forward cooperative system is capable of achieving a superior performance with the aid of Multiple-Symbol Differential Sphere Detection (MSDSD), when compared to conventional differential detection (CDD) for transmission over time-selective channels. However, the conventional broadcast/cooperative twin-phase based relaying protocol encounters a 50% throughput loss imposed...
This paper considers a secondary user (SU) sharing the spectrum licensed to a primary user (PU) if limited interference caused to the latter can be guaranteed. In particular, besides the interference power constraint at the PU to protect the PU, the transmit power of the SU is also considered. Under such a setup, we consider the average bit error rate (BER) as the performance metric for the SU, and...
This paper presents the performance analysis of a realistic Smart Utility Network (SUN) system with low duty signaling design. The main focus of this paper is to evaluate the performance of the SUN system based on the specifications in an on-going industrial standardization activity, the IEEE 802.15.4g. For this purpose, a theoretical framework is constructed to model the transceiver with low duty...
A Modified high-throughput time-hopping/directsequence (TH/DS) multiple access ultra-wideband (UWB) system using N-ary biorthogonal pulse position modulation (BPPM) is proposed and analyzed. Unlike to the conventional TH/DS system using the fixed and non-overlaid TH slots, the proposed TH/DS system is able to use the whole frame period to perform TH and BPPM. The average symbol error rate (SER) of...
Power conservation for maximizing the lifetime of the limited battery powered ad hoc networks are one of the most important factors in a network design. Transmitting at high power may assure network connectivity but sacrifice network lifetime and increases the interference as well. Meanwhile transmitting at lower power reduces the interference on the expense on network robustness. We investigate the...
In this paper, the performance analysis for a dual-hop Amplify-and-Forward relaying network is extended to the context of impulse radio ultra-wideband. Due to multiple accesses,the interference distribution is not Gaussian. We propose a symmetric α-stable model compatible with the impulsive nature due to its heavy tailed distribution. Taking advantage of the stability property, we develop...
Recent works on multi-user transmission techniques have shown that the linear growth of capacity in single user MIMO system can be translated to the multi-user MIMO scenario as well. In this paper, we propose a method pursuing performance gain of vector perturbation in multi-user downlink channels. Instead of exploiting the maximum available mobile users for communication, we employ small part of...
This paper considers the detection problem for fading channels in the presence of interference when both the transmitter of interest and the interferers employ practical modulation schemes. It is shown that, for Rayleigh fading, it is possible to obtain symbol error rates that have the same dependence on the received signal-to-noise ratio as when transmission is interference-free. This is achieved...
In this paper we focus on finding a suitable Link Adaptation (LA) algorithm which is implemented as Channel Quality Indicator (CQI) selection technique in the 3GPP Long Term Evolution (LTE) system. The potential of Link Adaptation in the LTE system is not fully exploited. Therefore in our study, we compare the performances from different LA algorithms in the LTE system. The presented LA algorithms...
The minimization of the overall power consumption of wireless networks while satisfying a certain throughput and error rate constraint is investigated. The total power dissipation includes the radiated power as well as the circuit power consumption. In the context of battery operated short range communication, where low power, low cost and small size are key requirements (e.g. standard IEEE 802.15...
Mitigating non-stationary narrowband interference from a continuous phase modulation (CPM) signal is a challenge due to the correlation present in CPM signal samples. For such a scenario, use of a time-varying linear prediction error filter (TVLPEF) based on a decorrelating time-varying autoregressive (DTVAR) model was proposed earlier. TVLPEF based mitigation of the interference from a CPM signal...
In this paper, we propose the precoder with hidden pilots for orthogonal frequency-division multiple access (OFDMA) systems in order to enhance the transmission efficiency of the system and reduce peak-to-average power ratio (PAPR) which is the problem in OFDMA uplink. In wireless communication systems, the way to improve transmission efficiency is 1) to reduce bit error rate (BER) or 2) to increase...
As an alternative to the OFDM transceiver, single carrier frequency domain equalization (SC FDE) based transceiver has received much attention because of its simple implementation and low peak to average power ratio (PAPR). In this paper, a minimum mean square error (MMSE) FDE for single carrier block transmission is presented to effectively equalize the channels with high frequency selectivity such...
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