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In this paper, two non-ideal effects, carrier frequency offset (CFO) and IQ imbalance, are jointly compensated for an orthogonal frequency division multiplexing (OFDM) system. Based on the two identical sequences in the preamble, a LS-based method is proposed to estimate both CFO and IQ imbalance. This method has much lower complexity than the state-of-art expectation-maximization (EM) approach. Simulation...
In this paper, we investigate an incremental opportunistic relaying scheme where the selected relay chooses to cooperate only if the source-destination channel is of an unacceptable quality. In our study, we consider regenerative relaying in which the decision to cooperate is based on a signal-to-noise ratio (SNR) threshold and takes into account the effect of the possible erroneously detected and...
In this paper, we propose an analytical framework on the exact computation of the average capacity of multihop transmission over amplify-and-forward relay fading channels. Our approach relies on the algebraic combination of Mellin and Laplace transforms to obtain exact single integral expressions which can be easily computed by Gauss-Chebyshev Quadrature (GCQ) rule. As such, the derived results are...
Air bandwidth is a precious resource for wireless communication. Multiple-antenna (MIMO) systems enable an increase in channel capacity without increasing the air bandwidth. An iterative demapping and decoding at the receiver improves the communications performance remarkably. However, MIMO demapping and channel decoding have a high computational complexity. Energy consumption, latency and throughput...
The focus of this paper is on the precoding and feedback strategies for a radio backhaul link between an access base station (ABS) and the hub base station (HBS) in the presence of mobile stations (MSs). In this paper it is assumed that the access and the backhaul links are simultaneous and use the same frequency band. Two feedback links are exploited at the ABS in order to optimize the communication...
We are motivated to exploit the broadcast nature of a radio medium in combating its unreliable and time-varying characteristics. This leads to cooperative transmission where a neighbor node keeps a copy of an overheard packet and helps in retransmitting the overheard packet to its intended destination when the original transmission fails. Cooperative transmission improve wireless network performance...
This paper proposes an adaptive bandwidth control scheme for autonomous distributed networks. Based on the consideration that the carrier sense multiple access with collision avoidance (CSMA/CA) is not efficient in terms of throughput due to its strict collision avoidance process, this paper employs a dynamic spectrum control (DSC) in which a certain number of discrete spectra having the highest signal...
We study the physical layer design of a distributed time-division multiple access (TDMA) protocol for wireless body area networks (WBAN). The distributed TDMA scheme is derived from a bio-inspired algorithm known as Pulse-Coupled Oscillator (PCO), in which each node in the network updates its state based on its knowledge of the neighborhood. ON-OFF ultra wide band (UWB) modulation is used by the sensors...
Along with LTE-Advanced system and standardization investigation progress, the requirement for verifying relevant key technologies become more and more urgent. This article summarizes the progress of Huawei 4G Test-bed “HEART” (Huawei Experimental Advanced Radio Test-bed). CoMP technology is considered as a launch point to build up this test-bed competence. Some initial analysis and results are addressed...
This paper proposes a number of novel uses for 3D location and environmental geometry information to enhance the performance of the wireless physical layer. In the context of this paper, such information is obtained in real-time from a mobile operative carrying the ViewNet system. A location-based multi-user scheduler is proposed to exploit multi-user diversity by choosing users with wide angular...
Exact average capacity results for L-branch coherent equal-gain combining (EGC) in correlated and uncorrelated fading channels are not known. This paper develops a novel framework (approach) for capacity analysis of L-branch EGC in generalized fading channels. In addition, Gamma shadowed generalized Nakagami-m fading model is proposed in order to statistically model the fading environments in high...
The throughput of conventional wireless multicast systems is limited by the multicast user with the lowest channel quality, which leads to a very low throughput especially if the number of users is large. In this paper, we show that hybrid-automatic repeat request with Chase combining (HARQ-CC) is a promising technique to overcome this problem and optimize the transmission rate of wireless multicast...
In wireless dual-hop decode-and-forward (DF) relaying networks, multiple relay stations (RS) and users construct a multiple-in-multiple-out (MIMO) broadcast channel (BC). Due to unpredictable decoding failure, scheduling the transmission for the decode-and-forward broadcast channel (DFBC) should depend on not only channel qualities but also the availability of errorless data at individual RSs. Based...
In this paper we investigate channel state information (CSI) feedback strategy for a basestation (BS) scheduling multiple users for data transmissions in the downlink. For the purpose of fair provisioning of service among users with possibly heterogeneous channel statistics, we adopt scheduling algorithms based on scores: specifically the maximum quantile (MQ) scheduling is used as one of such schedulers...
In this paper indoor wireless Infrared (IR) technology for healthcare monitoring is studied. Monitoring provides a continuous and reliable vital sign measurement to secure patient staying in the hospital. Considering that patient moving is inevitable, we focus on a mobile IR channel based on diffuse propagation. A model of mobile channel is developed through the study of statistical distributions...
Cooperative decoding is powerful technique for establishing good quality TV broadcasting. In cooperative decoding, some TV receivers, nodes, are cooperated, each other. These share the received information signal and thus obtain good quality information signal. Incremental-Maximum Ratio Combining (I-MRC) is one of the cooperative decoding methods. In I-MRC, the best condition's node and second one...
In this paper we consider an IEEE 802.15.4-based Wireless Body Area Network, where wearable sensor devices are distributed on a body and have to send the measured data to a coordinator. The Carrier Sense Multiple Access with Collision Avoidance algorithm defined by the standard is used as Medium Access Control protocol, whereas different modulation schemes are assumed to be available at the physical...
During recent years Wireless Body Area Networks (WBANs) have been experienced continuous developments by researchers both in academia as well as industry due to its capabilities and various promising applications, for instance, in the areas of healthcare, sports, military, etc. One of the crucial requirements in designing a WBAN, especially, for the healthcare applications is network reliability since...
In current wireless standards like 3GPP LTE or IEEE 802.16 / WiMAX multiple access is based on orthogonal signalling using single-carrier frequency-division multiple access (SC-FDMA) or orthogonal frequency-division multiple access (OFDMA). Links between a base station and different terminals use mutually orthogonal radio resources. This paper studies potential gains in average cell throughput by...
In this work we consider the allocation of buffer space to data streams sharing a common high-speed wireless transmitter. As an example, we focus on an OFDMA-based downlink system scenario. Scheduling for maximum throughput has been extensively studied in the literature. However, the practically interesting case of a finite buffer has not been sufficiently addressed before. Especially in the case...
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