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In this paper, we analyse the delay performance of a point-to-multipoint cognitive radio network which is sharing the spectrum with a point-to-multipoint primary network. The channel is assumed to be independent but not identically distributed and has Nakagami-m fading. A constraint on the peak transmit power of the secondary user transmitter (SU-Tx) is also considered in addition to the peak interference...
Coordinated multi-point (CoMP) transmission is considered as an efficient technique to improve cell-edge performance as well as system spectrum efficiency. In CoMP-enabled systems, a cluster of coordinated base stations (BSs) are typically assumed to be connected to a control unit (CU) via backhaul links, and the provided performance gain relies heavily on the quality of the channel state information...
This paper studies a spectrum sharing cognitive radio (CR) network coexisting with a primary network. In particular, the channel state information (CSI) between the secondary transmitter (STx) and the primary receiver (PRx) is assumed to be outdated due to channel feedback latency. We assume that the secondary user (SU) shall satisfy a given delay quality-of-service (QoS) constraint as well as the...
This work considers the scheduling problem for the packets with strict maximum tolerable delay (deadline) constraint. We discuss a multiuser scheduling scheme which schedules the users based on their instantaneous channel conditions, packet deadline and backlog of the buffered packets. The scheme is analyzed in large system limit for the single and multicell cases. The aim is to minimize the system...
To better exploit the spectrum resources a wireless sensor network can be used to assists a secondary cognitive radio network by providing information about the current primary spectrum occupancy. In this paper we study the performance of the secondary network when it is co-located with and having similar cell size as a mobile primary network that uses a cellular reuse pattern with seven frequencies...
Overlap frequency-domain equalization (FDE) requires no cyclic prefix (CP) insertion. In this paper, a new minimum mean square error (MMSE) weight is derived for the overlap FDE. In the previous paper, the MMSE weight for overlap FDE is derived by approximating the IBI as a white Gaussian variable. However, the IBI is an independent colored noise. We derive a new MMSE weight by taking into account...
We address the analytical design of a communications system that seeks to provide timely safety information for drivers who are unaware of an imminent collision. We develop a model to characterize the delay requirements needed to prevent such collisions. By simultaneously addressing the multi-user interference and propagation effects such as path loss and fading, we then analytically derive the optimal...
A Sensor Network Aided Cognitive Radio Network uses the concept of a wireless sensor network that assists a cognitive radio network by providing information about the current primary spectrum occupancy. In this paper we study the performance of the cognitive network for various cell sizes and transmit power levels when deployed co-located with a mobile primary system that uses a cellular reuse pattern...
In this paper, we investigate the outage performance of a dual-hop relaying systems with partial relay selection and feedback delay. The analysis considers the case of Rayleigh fading channels when the relaying station as well as the destination undergo mutually independent interfering signals. Particularly, we derive the cumulative distribution function (c.d.f.) of a new type of random variable involving...
In the paper, we consider the end-to-end routing and link scheduling problem for multi-hop wireless sensor networks. The efficient link scheduler under our consideration is intended to assign time slots to different users so as to minimize channel usage subject to constraints on data rate, delay bound, and delay bound violation probability. We also present a coupled robust multi-path routing structure...
This paper investigates the downlink system level performance for Layer-3 (L3) and Layer-1 (L1) relays with orthogonal frequency division multiple access (OFDMA) used in LTE-Advanced. Various practical factors are taken into account in the evaluations such as the processing delay and upper-bound of the amplifier gain of the L1 relay, capacity limitation of the backhaul channels, and empty buffer status...
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...
The law of the time to transmit a packet from a node to its intended receiver, in a wireless network with randomly deployed, multiple-antennas equipped nodes, whose communication is impaired by fading and interference, is investigated. SINR-based coverage at the physical layer is assumed, and the useful signal strength is shaped through either cooperative or non-cooperative beamforming. In particular,...
Communication between two neighboring nodes is the most basic operation in wireless networks. Yet very little research has focused on the local delay, defined as the mean time it takes a node to connect to a nearby neighbor. This problem is non-trivial when link distances are random but static, as is the case when the node distribution of a static network is modeled as a stochastic point process....
Time-of-arrival (ToA) estimation technique used with ultra-wideband (UWB) transmission can be used for accurate indoor ranging. In the indoor multipath rich environment, these techniques often suffer from significant inaccuracy in ranging estimation. It is generally believed that the main cause of the ToA estimation error in the Line-of-sight (LoS) scenario is noise, usually modeled as white Gaussian...
Railway operations is closely related to people's livelihood, and the reliability, availability, maintainability and security of railway communication system are the focus and key issues of railway information construction. There are series of problems, such as the deterioration of communication performance (difficult to meet the needs of train control and train scheduling) because of the wireless...
This paper analyzes the interference in Direct Sequence Spreading Spectrum (DSSS) systems with Selective RAKE (SRAKE) receivers where channel delay is comparable with spreading sequence length. We build an accurate output model of SRAKE receiver and derive the output Signal to Interference-Noise Ratio (SINR) and Bit Error Rate (BER) of SRAKE receiver, taking multipath effect into consideration. Based...
Statistical models for handover scenarios are necessary in order to identify key parameters and to allow proper benchmarking for handover techniques. This is quite a difficult task, since many assumptions have to be made, resulting in a loss of generality. Efforts towards the generation of such models were already made. Although these models show insights into trade offs, they leave some open questions...
Power control is one of the major parts of cellular communication system. The power control helps maintain quality of service of the communication link. In this paper, a simple proportional integral (PI) control is used in the Code Division Multiple Access (CDMA) radio system to maintain the signal to noise ratio (SNR) around a desired level under channel fading environment with multiple access interference...
Research on anti-fading is an important problem in wireless communication system. The high-efficiency Extended Binary Phase Shift Keying (EBPSK) modulation has very good anti-fading characteristics because of the existing of the guard interval. The EBPSK transmission system is simply introduced firstly. Then the transmission performance of EBPSK signal in fading channel model is analyzed. Simulation...
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