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In this paper, a mixture gamma (MG) distribution that is highly accurate unified approximate approach is used to model the intractable statistical properties of α — κ — μ shadowed fading channels. The α — κ — μ shadowed fading channel contains the generalized α — κ — μ fading and gamma distribution which represent the impact of multipath fading and shadowing, respectively. The performance of communication...
THz impulse communications is a new system concept based on an imaging radar that we have been developing for biomedical imaging applications the past ten years. Its hybrid architecture combines the high-peak-power and spread-spectrum of photoconductive-switch transmitters with the high-responsivity and broad-bandwidth (RF and video) of Schottky-rectifier receivers. The data is impressed by simple...
In this paper, we analyze and evaluate the performance of multibranch scan-and-wait combining (SWC) receivers over arbitrarily correlated and not necessarily identically distributed Nakagami-m fading channels. A fast convergent infinite series representation for the SWC output signal-noise ratio (SNR) is firstly presented. This expression is then used to obtain analytical expressions in the form of...
This paper proposes a novel operation for hybrid Free Space Optics (FSO)/Radio Frequency (RF) systems. We add a new function to current hybrid systems, which is responsible for operation mode selection (OMS). A dynamic OMS policy is proposed by taking intelligent control decisions at the transmitter taking into account states of both queue and channel (i.e. queue-aware and channel- aware). System...
Direct RF undersampling technique has been focused to realize compact and low power consumption receiver. This architecture does not require the LO section and downconverter, but it requires relatively high gain LNA. In this paper, we investigate the usage of power switching (intermittent-mode) LNA to reduce the power consumption. When we simply apply the intermittent-mode LNA, the SNR of the RF undersampling...
In this paper, we consider the simultaneous wireless information and power transfer for the spectrum sharing (SS) in cognitive radio (CR) systems with a multi-antenna energy harvesting (EH) primary receiver (PR). The PR uses the antenna switching (AS) technique that assigns a subset of the PR's antennas to harvest the energy from the radio frequency (RF) signals sent by the secondary transmitter (ST),...
The problem of spectrum congestion is a big challenge for the researchers now a days. This problem can be solved by cognitive radio. With the help of cognitive radio, the spectrum which is not being used by any licensed user, at a particular time period, can be used by secondary or cognitive radio user, making more efficient spectrum utilization. This is done by spectrum sensing process. Among many...
Performance of a modified switch and examine combining (M-SEC) diversity receiver [1] with arbitrary number of branches is analyzed over independent generalized gamma fading channels. Expressions for the average output signal-to-noise ratio and amount of fading of the combiner output signal are obtained. The average bit error rate for non-coherent modulation schemes and the average Shannon channel...
In this paper, the performance analysis of two different diversity models in indoor milli-meter wave communication in presented. Two diversity models considered here are Switch and Stay combining(SSC) diversity and Switch and Examine combining(SEC) diversity. Arbitrary number of received signals are examined and processed using the above mentioned diversity techniques. The L outputs of each combiner...
Selection diversity (SD) represents an attractive solution in various wireless communication scenarios, since it offers relatively low complexity and improved performance. However, in many practical situations the continuously monitoring of all the available diversity paths, which is mandatory in SD schemes, adds unnecessary overhead to the systems. In this paper, in order to alleviate this complexity,...
5th Generation (5G) small cells are expected to satisfy the increasing demand for wireless data traffic. In the presence of large scale dense and randomly deployed cells, autonomous and distributed configuration mechanisms are highly desirable. However, small cells typically serve a small number of users, such that sudden traffic imbalances between downlink (DL) and uplink (UL) are expected in the...
Distributed switch-and-stay combining (DSSC) has been envisioned as an effective transmission technique to achieve spatial diversity in a distributed fashion, with low implementation complexity. In this paper, we take a step further to incorporate DSSC into spectrum-limited environment, where the operating nodes have to share the frequency radio spectrum with licensed users. In particular, by deploying...
Diversity Combining techniques have been of great importance as far as improvising of performance is concerned in wireless communication. In this paper, a new hybrid diversity scheme has been proposed for Rayleigh fading channel in which L number of maximal ratio combining (MRC) receiver, each MRC combiner having M branches at its input, are selection combined to obtain the final output at the receiver...
The performance of Switch and Stay Combiner (SSC) over ‘independent’ and ‘independent and identically distributed’ (i.i.d.) K fading channels is analyzed and evaluated in this paper. The K distribution used to model composite fading channels can be obtained by averaging the conditional Rayleigh Probability Density Function (PDF) over the Gamma PDF. Expressions for the outage probability, moments of...
The concept of heterogeneous networks (HetNets) has been introduced in LTE-Advanced systems in order to improve overall capacity and cell-edge user performance. However, such uncoordinated deployments sharing the same spectrum present new interference issues that are difficult to combat with conventional interference management schemes. In this paper interference issues in a macro-femto scenario in...
In this paper, we consider a switch-and-examine combining (SEC) diversity scheme operating over independent and identically distributed (i.i.d) branches assuming an α-μ fading channel. We derive expressions for the average symbol error rate (ASER) for a class of coherent modulation techniques considering this fading model as well as expressions for the ergodic capacity under the same assumptions....
In wireless sensor networks, the PHY layers use robust modulations and spread spectrum techniques as in IEEE 802.15.4, which often allows to capture a frame successfully even if it collides with another transmission. In this work, we propose eMiM (Enhanced MiM), a new capture scheme that takes into account both SINR and the collision timing in the switching decision. We have carried out extensive...
In this paper, we analyze a diversity system with the transmit antenna selection (TAS) at the transmitter and the switch-and-examine combining (SEC) at the receiver over a Nakagami-m fading channel. This system has lower complexity as compared to the TAS schemes with maximum-ratio combining and generalized selection combining at the receiver. Furthermore, the TAS/SEC scheme requires a smaller number...
The performance of Free Space Optical (FSO) links is severely influenced by misalignment of optical nodes. Pointing errors and misalignment can be caused as a result of unintentional optical heads sway induced by external sources. Misalignment can be also considered intentionally under some cases, e.g. mobile FSO, to establish optical connections while maintaining node mobility. In this paper, the...
The performance of noncoherent binary frequency shift keying (BFSK) with dual-branch postdetection switch-and-stay combining (SSC) in two-wave with diffuse power (TWDP) fading is studied. A closed- form expression for the average bit error rate (BER) of noncoherent BFSK with dual-branch postdetection SSC is derived. Previously obtained results on the performance of predetection SSC in TWDP fading...
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