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The performance of millimeter wave (mmWave) networks is limited by severe blocking effects. Mobile relaying exploiting possible two-hop line-of-sight connections is a strong candidate for coverage extension and consistent user experience in mmWave networks. Here, relaying based on opportunistic analog beamforming is investigated, and sets of fixed beams are used for cell discovery, relay discovery...
We consider two-hop Device-to-device (D2D) relaying in multi-cell downlink networks. D2D relaying is envisioned to be a promising cell coverage extension technique, which can provide improved cell-edge performance without a dense infrastructure deployment. Relaying complicates the resource allocation and interference management in multi-cell networks. We first study the aggregate co-channel interference...
Code-Division Multiple-Access (CDMA) [1] is widely used in both civil and military applications. It does take advantages from the system characteristics. For example, higher data rate and user capacity, better multipath resolution [2] and resistance to jamming, low probability of interception, accurate timing and ranging, and more importantly, stronger ability to suppress interference and jamming...
Small cell networks are key components in 5G networks to boost the network capacity, improve spectrum and energy efficiency, and enable flexible and new services. Due to the flexible spectrum access among and flexible deployment of small cells, the inter- cell coordination becomes critical for the performance of the network. In this paper, based on the key concept in software defined networking (SDN)...
This paper puts forwards an on-line reinforcement learning framework for the problem of traffic offloading in a stochastic Markovian heterogeneous cellular network (HCN), where the time-varying traffic demand of mobile terminals (MTs) can be offloaded from macrocells to small-cells. Our aim is to minimize the average energy consumption of the HCN while maintaining the Quality-of-Service (QoS) experienced...
The cross- and co-tier interference creates the challenges to facilitate the concept of heterogeneous cellular networks (HCNs) in practice. In this paper, we establish a combined learning framework to autonomously mitigate the destructive interference. The macrocell is modeled as the leader and protects itself through pricing the interference from small-cells, which are the followers in the stochastic...
This paper investigates energy efficiency for the two-tier femtocell networks through combining game theory and stochastic learning. With the Stackelberg game formulation, a hierarchical reinforcement learning framework is developed to study the joint expected utility maximization of macrocells and femtocells. The macrocells behave as the leaders and the femtocells are followers during the learning...
Given the elasticity, dynamicity and on-demand nature of the cloud, cloud-based applications require dynamic models for Quality of Service (QoS), especially when the sensitivity of QoS tends to fluctuate at runtime. These models can be autonomically used by the cloud-based application to correctly self-adapt its QoS provision. We present a novel dynamic and self-adaptive sensitivity-aware QoS modeling...
As energy saving and environmental protection become an inevitable trend, researchers need to shift their focus to “green” oriented architecture design. Recent advances in the area of cognitive radio (CR) have significant potential towards “green” communications. One of the critical challenges for operating CRs in a wireless mesh network is how to efficiently allocate transmission powers and frequency...
In this paper we introduce a reliable multicast concept for Device-to-Device (D2D) communication integrated into cellular network. In addition to the introduction of the basic concept, initial simulation results are presented as well. Clustering closely located devices which have local communication needs is a feasible and efficient way of solving the increasing data traffic requirements in the future...
Cognitive wireless mesh networks have great potential to green communication. One of the critical challenges for realizing such networks is how to adaptively match transmit powers and allocate frequency resources among secondary users of the licensed frequency bands whilst maintaining the quality-of-service (QoS) requirement of the primary users, even in mutually entangled interferences environment...
In this paper, we analyze the challenges of the interference environment in a hybrid network that consists of the device-to-device (D2D communication based ad-hoc connections and conventional cellular connections. Accordingly, time hopping (TH) based radio resource allocation schemes aiming to improve the robustness of the hybrid network are proposed. The performance improvement even with the simple...
In a cellular network system one way to increase its capacity is to allow direct communication between closely located user devices when they are communicating with each other instead of conveying data from one device to the other via the radio and core network. The problem is then when the network shall assign direct communication mode and when not. In previous works the decision has been done individually...
As the limited spectrum resource becoming over crowded, cognitive wireless mesh networks have great flexibility to improve the spectrum utilization by opportunistically accessing the authorized frequency bands. One of critical challenges for realizing such networks is how to adaptively allocate transmit powers and frequencies among secondary users (SUs) while maintaining the quality of service (QoS)...
Future wireless access networks, characterized by a large number of small cells densely distributed in metropolitan area, are likely to be the dominating form of future wireless communications. It is expected that the dynamic spectrum access (DSA) enabled by cognitive radio (CR) technologies will act as a key for their success. Considering the high cell density and the large size of network, the spectrum...
The uplink total interference and the ratio of interference from inter-cell to from intra-cell of TD-SCDMA base station is analyzed in this paper by the method of simulation. The results of uplink ratio of interference from other cells to from own cell and noise rise of base station are given with smart and directional antenna respectively. Some suggestions are also provided for TD-SCDMA network planning.
In order to minimize interference with primary users (PU), cognitive radios should operate multidimensionally over time, frequency, and space. This paper addresses the problem with power control and predictive frequency selection. Both the methods are coupled with spectrum sensing. The proposed frequency selection method minimizes the amount of channel switches, which increases the capacity of the...
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