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Ad hoc networks continue to be severely interference limited. One approach to increase capacity is to go to millimeter wave (mmWave). Higher bandwidth but also directional antennas to reduce interference. Another approach is to stay at conventional frequencies but use techniques like interference alignment (IA). In this paper, we derive the scaling laws for dense mmWave ad hoc networks with directional...
Many works attributed the successful reception of concurrent transmission (CT) to the constructive interference. However, due to the inevitable carrier frequency offset (CFO) and the resulted beating effect, the claim of constructive interference is actually not valid. To clarify the reason behind the successful receptions under CT, we conduct extensive evaluations and identify the following findings...
This paper considers a hybrid two-stage space-time receiver structure for uplink millimeter wave (mmW) based systems, where the user terminals (UTs) and the base station (BS) are equipped with a large antenna array and the number of radio frequency (RF) chains is lower than the number of antennas. In the first stage the analog transmit and receive beam-formers/precoders are computed for each UT —...
This paper conducts a comparative study for zone differentiation techniques using two types of linearly polarized directional antennas. The antenna types are microstrip single patch and microstrip array patch. We employed array patch antenna with three elements in a previous work to track and identify hospital staff who approach patient's bed space. However, there was an inaccuracy in detection due...
Cache-enabled device-to-device (D2D) communication is a promising technique to offload the core traffic and cache deployment is important in achieving the benefits brought by caching. While rare considered optimal caching deployment from the perspective of energy efficiency. In fact, cache deployment will certainly influence the distribution of active transmitters, network interference and power consumption,...
Enabling device-to-device (D2D) communication in cellular network is shown to be a promising candidate in the future fifth generation (5G) wireless network. Specifically, the hybrid architecture leads to flexible and efficient resource allocation for cellular users and D2D users, thereby enhancing utilization of spectrum resources. However, if not properly handled, mutual interference will be significantly...
In a spectrum-sharing heterogeneous network (HetNet), low-power cells such as femtocells are deployed jointly with macrocells, thereby generating interference. To tackle this critical issue in HetNets, we advocate a new interference mitigation concept that combines uncoordinated use of both interference cancellation and interference avoidance at the receiver and transmitter sides, respectively, to...
In this paper, we propose a closed-form interference alignment and cancellation scheme for the three-user multiple-input multiple-output (MIMO) X-channel network without symbol extension. We first demonstrate the basic principle of how to design the beamforming matrices for this set-up, then we estimate the sum rate achievable under perfect and imperfect channel state information. It is shown that...
In this paper, we consider two base stations (BSs) which maximize the achievable rate for two users connecting to each BS and sharing channel state information (CSI) in a multi-cell processing (MCP) framework. We propose a two way channel estimation or prediction process. Such framework has promising outcomes in terms of feedback reduction and achievable rates moving the system from one with unknown...
Extensive deployment of heterogeneous small cells over existing macrocell cellular networks forms the Ultra-dense Small cell Network (USN). USN has emerged as a key networking architecture in 5G wireless networks. It can improve network coverage and boost system capacity. However, the dense overlapped deployment of small cells leads to a complex interference problem. In this paper, we jointly implement...
In this paper, we propose a new method for mitigating narrowband interference in Ultra-WideBand (UWB) communication systems based on Orthogonal Frequency Division Multiplexing (OFDM). Spreading data symbols to some subcarriers, the interference is effectively mitigated. However, the range to be spread for the interference is limited in conventional methods. In the proposed method, we widen more the...
An 11 element crossed bowtie array antenna has been developed for use in Digital Video Broadcasting-Television (DVB-T) based passive radar. Simulation results of the array show a gain of 6 dB and measurements in anechoic chamber show more than 20 dB cross-polarized isolation. Co- and cross-polarized passive radar measurements of a Cessna 172 aircraft have been conducted and the results are compared...
This paper aims at studying underwater acoustic OFDM communication systems interfering with each others in the same channel. We propose a decentralized spectrum sharing method that minimizes the total power consumed while satisfying a constraint related to their information rate. The considered systems are supposed noncooperative, i.e. unable to communicate with each others so that they cannot agree...
In modern wireless networks especially in Machine-to-Machine (M2M) systems and in the Internet of Things (IoT) there is a high densities of users and spatial reuse has become an absolute necessity for telecommunication entities. This paper studies the maximum throughput of Carrier Sense Multiple Access (CSMA) in scenarios with spatial reuse. Instead of running extensive simulation with complex tools...
The sum rate maximization problem in Interference Alignment (IA) is hard to be solved, for the sum rate function is non-convex. The Weighted Minimum Mean Square Error (WMMSE) algorithm settles this problem by converting the original problem into an equivalent convex one. In this paper, an enhanced version of the WMMSE algorithm is presented, which takes the statistical information of the channel estimation...
We present upper and lower bounds on the per-user multiplexing gain (MG) of Wyner's circular soft-handoff model and Wyner's circular full model with cognitive transmitters and receivers with cache memories. The bounds are tight for cache memories with prelog μ that exceeds 2/3D in the soft-handoff model and exceeds D in the full model, where D denotes the number of possibly demanded files. In these...
Zero-Forcing (ZF) algorithm is used to eliminate interference in small scale interference network. With the number of users increasing, the traditional ZF algorithm does not work effectively due to the fact that the channel matrix cannot provide sufficient dimensions to isolate interference. In this paper, we propose a Coordinated Zero-Forcing Beamforming with Clustering(CZFC) scheme to improve the...
In the recent fifth generation (5G) research, filter bank multi-carrier (FBMC) technique is one of the competitive substitutes to orthogonal frequency division multiplexing (OFDM). The conventional FBMC schemes, such as FBMC staggered-modulated multitone (FBMC-SMT) and frequency spreading FBMC (FS-FBMC), have the intrinsic time-domain interference which is caused by the overlap of symbols and depend...
In this paper, we study robust spectrum sharing under channel uncertainty in a cognitive radio network (CRN), where a great number of secondary users (SUs) and a primary user (PU) coexist with each other sharing the same frequency spectrum. Considering the practical challenge that the channel gain between SU transmitters (SU-Txs) and PU receiver (PU-Rx) is typically uncertain, a probabilistic interference...
While obtaining the channel state information (CSI) required to perform Interference Alignment (IA) in a centralised MIMO network is a challenge, this is compounded in unplanned wireless networks that may be decentralised - not to mention composed of devices with varying degrees of complexity and capability. This is of particular interest to heterogeneous networks and the Internet of Things (IoT)...
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