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Closed-form expressions of the precisely accurate error probability are given for equal gain diversity in generalized fading distributions, namely ??-?? and ??-??, considered by da Costa and Yacoub.
An adaptive power control scheme for cognitive radio system (CRS) in Rayleigh fading channel is proposed. The transmit power of a secondary user (SU) is adjusted in Rayleigh fading to maximize the constant output signal-to-noise ratio (SNR) at an SU receiver while keeping the interference to a primary user (PU) under given constraints. To calculate the maximum constant output SNR at the SU receiver...
In this paper we investigate spectrum sensing for cognitive radio (CR) by using multiple spectrum sensors. We explore sensing schemes based on soft information combining, hard information combining and a two-stage detection scheme that uses both soft information combining and hard information combining. The two-stage detection scheme is shown to provide improved performance compared to sensing based...
This paper presents throughput and error performance analysis of the proposed space-time resource management (STRM) scheme for a multi-Gbps millimeter-wave system. The proposed STRM allows multiple peer-to-peer communication links to occupy the same time-division-multiple-access (TDMA) time slot, in contrary to the conventional TDMA system that allocates only one time slot to one communication link...
AbstraAbThis study addresses detection of primary users (PUs) for cognitive radio system (CRS) with distributed spectrum sensors (DSSs) in Rayleigh fading environment. Two sensing schemes using DSSs that employ energy detection (ED) are investigated as cooperative sensing and collaborative sensing. For the cooperative sensing, each DSS makes hard decision after sensing and transmits the information...
This paper investigates the impact of adjacent channel interference (ACI) and co-channel interference (CCI) on the error performance and throughput of a multi-Gbps millimeter-wave wireless personal area network (WPAN) system in both residential multipath line-of-sight (LOS) and non-LOS (NLOS) environment. It is found that the ACI that causes 0.5dB degradation in signal-to-noise ratio (SNR) for BPSK,...
The function of a cognitive radio system (CRS) can be classified as cognitive engine (CE) and sensing. The CE fulfills spectrum analysis and decision making of spectrum access. The sensing function is realized by either a CR node or distributed spectrum sensors. In this paper, we propose a sensing architecture, which adds new functional entities, sensing controller (SC) and sensing information processor...
Inter-symbol/frame interference analysis is presented for pulsed direct sequence (DS) and hybrid direct sequence time hopping (DS/TH) ultra-wideband (UWB) communications considering a frequency selective Nakagami fading channel. Following the analysis, error rate expressions are developed and performance comparison is presented for the systems. It is found that the performance of pulsed DS system...
Recent studies on spectrum sensing for cognitive radio (CR) reveal that sensing based on single CR may not provide reliable information due to the fact that signals degrade as a result of fading and shadowing. Hence, spectrum sensing based on multiple CR has been considered. In this paper we investigate a distributed sensing based on multiple spectrum sensors where the sensors are located outside...
Non-coherent UWB receivers provide robustness against multi path fading at low complexity. The analog front-end of these receivers, however, is susceptible to narrowband interference (NBI), thus requiring NBI mitigation capability. NBI identification and NBI parameter estimation is the first step towards implementing effective NBI mitigation. We propose an NBI detection and its center frequency identification...
A cognitive radio system (CRS) senses the radio spectrum environment and adaptively use unoccupied spectrum resource. The CRS should optimize between two conflicting goals for different applications. One is the minimization of interference to primary users and the other is the maximization of usage of spectrum opportunities of the secondary users. In this paper, we propose a dual-level management...
The paper presents a signal-to-noise ratio (SNR) mapping scheme for single-carrier (SC) frequency domain equalization (FDE) based millimeter-wave wireless personal area networks (WPANs). The effective SNR, defined as an average SNR over whole data frame after equalization, is a one-to-one mapper of the SNR in practical scenario in the sense of the same bit error rate (BER) performance. As the mapping...
One of the unique feature of cognitive radio systems is they can make use of temporarily idle spectral bands in an opportunistic manner. To achieve this however, robust sensing algorithm is required which otherwise incumbent services could suffer from interference. In this paper sensing algorithms based on energy detection and self-correlation detection are presented and compared. The self-correlation...
This paper investigates the adjacent channel interference (ACI) resistance of a multi-Gbps single carrier wireless personal area network (WPAN) operating in the 60 GHz millimeter-wave band. The significance of performance degradation due to ACI is investigated corresponding to varying factors such as types of modulation and radio frequency (RF) hardware impairments. The level of modulation scheme...
Multiple access analysis is presented for pulsed direct sequence (DS) and hybrid DS time hopping (DS/TH) ultra-wideband (UWB) communications considering a Saleh-Valenzuela type clustered frequency selective Nakagami fading channel. A general analytical framework is developed for modeling the multiple access interference (MAI) in low-duty systems that is substantially complicated than analysis of more...
This paper proposes a cross-layer unequal error protection (UEP) scheme that supports compressed video transmission in 60 GHz wireless personal area network (WPAN) systems. The proposed scheme combines MAC layer aggregation with PHY layer hierarchical modulation mapping, which offers better visual-quality transmission over conventional equal error protection (EEP). Computer simulations show that under...
This paper proposes the employment of trelliscoded-modulation (TCM) to improve error performance and/or to increase system throughput in a multi-gigabit physical layer (PHY) design for millimeter-wave 60 GHz wireless personal area network (WPAN) systems. Hardware impairments such as the 60 GHz power amplifier (PA) non-linear distortion and the 60 GHz phase-locked loop (PLL) phase noise (PN) are considered...
The paper presents a feasible frequency domain pre-equalization (pre-FDE) proposal in order to reduce the number of frequency domain equalizer (FDE) in a piconet. The pre- equalization scheme based on the cross-layer design on both physical layer and MAC layer is proposed and investigated in millimeter-wave 60-GHz wireless personal area networks (WPANs). The physical structure is designed so that...
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