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We consider a device-to-device (D2D) relay-assisted cellular network where mobile transceivers that are owned by self-interested users are incentivized to relay each other's data using tokens, which they exchange electronically to “buy” and “sell” downlink relay services. We formulate the decision problem faced by each UE, namely, the problem of deciding whether or not to relay, as a Markov decision...
We present a performance evaluation of ITLinQ and FlashLinQ, the two most popular schemes proposed to date to channelize D2D transmissions, i.e., to parse transmissions into noninterfering sets to be allocated to separate channels. Recognizing that it captures well the spatial characteristics of D2D networks, a stochastic geometry setting is utilized for this evaluation with the parameters of either...
In this paper, we define a collision area in a heterogeneous cellular network for the purpose of interference management between Device-to-Device (D2D) and conventional cellular (CC) communications. Currently, most D2D routing algorithms assume synchronized accurate location knowledge among users and the base stations. In reality, this level of location accuracy is difficult and power consuming in...
In this paper, we investigate the optimal spectrum leasing and sharing for dynamic spectrum access (DSA) network which actively shares its spectrum resource with a group of secondary users (SUs) for reaping revenue. The DSA aims at maximizing its total charge to the SUs based on their achieved throughput, while taking into account the additional power consumption of the primary user (PU) to overcome...
Licensed-assisted access (LAA) is a new operation mode of Long-Term Evolution (LTE) in the unlicensed spectrum currently under study in the 3GPP standardization forum. In order to coexist with Wi-Fi, some of the new functionalities required of LAA LTE include a mechanism for clear channel assessment based on listen-before-talk (LBT), discontinuous transmission on a carrier with limited maximum transmission...
Innovations enabling efficient spectrum utilization is a key element to optimize user experience with growing data demand. This paper discusses the approach of extending enhancements in cellular technology like LTE to unlicensed band for higher spectral efficiency and better user experience. A key challenge for such extension is the coexistence with legacy technology such as Wi-Fi. The description...
In this paper the authors discuss a problem of acquisition and reconstruction of a signal polluted by adjacent- channel interference. The authors propose a method to find a sub-Nyquist uniform sampling pattern which allows for correct reconstruction of selected frequencies. The method is inspired by the Restricted Isometry Property, which is known from the field of compressed sensing. Then, compressed...
Inter-Cell Interference Coordination (ICIC) has been identified for LTE as the main instrument for interference control. With ICIC, quality requirements can be guaranteed while avoiding the complexity of coordinated baseband processing approaches. However, most ICIC schemes proposed so far rely on centralized multi-cell scheduling algorithms that involve very heavy signaling overhead and, as a result,...
The existing works on analyzing/utilizing spectrum whitespace in Cognitive Radio Networks (CRNs) are either empirical studies lacking of theoretical guarantee, or local primary network information based inducing inaccurate analysis and estimation, or overlooking the spectrum whitespace details. Therefore, we propose to systematically analyze the spectrum whitespace in CRNs from a social network perspective...
Outage probability computation has been extensively studied in cellular radio systems where the interference is modeled by a sum of lognormal random variables. Since the sum of correlated lognormal random variables distribution does not have a closed-form expression, many approximation methods and bounds were proposed in the literature. However the accuracy of each method relies highly on the region...
We analyze Coordinated Multi-Point (CoMP) transmission and reception over heterogeneous wireless networks (HetNets). Our focus is on the design of a practical algorithm for joint resource allocation (joint scheduling) in each HetNet cluster. We present one such algorithm together with its detailed analysis and evaluation under two different approaches for obtaining and utilizing channel feedback from...
The problem of base station cooperation has recently been set within the framework of Stochastic Geometry. Existing works consider that a user dynamically chooses the set of stations that cooperate for his/her service. However, this assumption often does not hold. Cooperation groups could be predefined and static, with nodes connected by fixed infrastructure. To analyse such a potential network, in...
A Body Area Network (BAN) is a radio standard for wireless connectivity of wearable and implantable sensors located inside or in close proximity to the human body. Medical and some other applications impose stringent constraints on battery powered BAN reliability, quality of service, and power consumption. However, lack of coordination among multiple colocated BANs in the current BAN standard may...
Horizontal spectrum sharing occurs when multiple users share a given band of frequencies with no central control or coordination, and all users compete for access to the available spectrum. Depending on the actual approach used to allocate transmit power over available channels, mutual interference may affect user performance. Three types of horizontal spectrum sharing scenarios will be outlined in...
In this paper, a new overlay spectrum sharing protocol based on signal space diversity (SSD), is proposed for cognitive radio networks. The considered network comprises of one licensed primary transmitter/receiver (PT/PR) pair and one secondary transmitter/receiver (ST/SR) pair assisting for cooperation before transmitting its own signal on the licensed primary user's spectrum. The overall transmission...
Cognitive radio networks (CRNs) have become a popular research topic in recent years. Most existing CRN routing schemes focus on building a route that optimizes a single aspect of a network's performance, such as minimizing interference for primary users, or reducing the propagation delay or hop count. They do not consider the overall transmission performance for secondary users. In this work, our...
In smart cities, cellular network plays a crucial role to support connectivity anywhere and anytime. However, the communication demand brought by applications and services is hard to predict. Traffic in cellular networks might fluctuate heavily over time to time, which causes burden and waste under different traffic states. Recently, small cell was proposed to enhance spectrum efficiency and energy...
Time of arrival is a commonly used mechanism for geolocation. In many environments, multipath propagation of RF signals limits accuracy. Wide bandwidths reduce the impact of multipath propagation, but frequently results in interference from other devices. When the bandwidth is assembled from several measured sub-bands, there is an additional difficulty of a random phase offset between bands. In this...
Heterogeneous wireless systems such as a combination of mobile broadband wireless access (MBWA) and wireless local area network (WLAN) are candidates to attain the large capacity in the next generation mobile communication systems. For capacity expansion, small cells of multiple wireless network are deployed densely in these systems. Because a number of the cells overlap, users must discover a lot...
Communications play an important role during public safety operations. Since the current communication technologies heavily rely on the backbone network, the failure of base stations (BSs) due to natural disasters or malevolent attacks causes communication difficulties for public safety and emergency communications. Recently, the use of unmanned aerial vehicles (UAVs) such as quadcopters and unmanned...
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