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Cross-Layer Resource Allocation Scheme Under Heterogeneous Constraints for Next Generation High Rate WPAN  [PDF]
Ayman Khalil,Matthieu Crussiere,Jean-Francois Helard
Computer Science , 2010, DOI: 10.5121/ijcnc.2010.2312
Abstract: In the next generation wireless networks, the growing demand for new wireless applications is accompanied with high expectations for better quality of service (QoS) fulfillment especially for multimedia applications. Furthermore, the coexistence of future unlicensed users with existing licensed users is becoming a challenging task in the next generation communication systems to overcome the underutilization of the spectrum. A QoS and interference aware resource allocation is thus of special interest in order to respond to the heterogeneous constraints of the next generation networks. In this work, we address the issue of resource allocation under heterogeneous constraints for unlicensed multiband ultra-wideband (UWB) systems in the context of Future Home Networks, i.e. the wireless personal area network (WPAN). The problem is first studied analytically using a heterogeneous constrained optimization problem formulation. After studying the characteristics of the optimal solution, we propose a low-complexity suboptimal algorithm based on a cross-layer approach that combines information provided by the PHY and MAC layers. While the PHY layer is responsible for providing the channel quality of the unlicensed UWB users as well as their interference power that they cause on licensed users, the MAC layer is responsible for classifying the unlicensed users using a two-class based approach that guarantees for multimedia services a high-priority level compared to other services. Combined in an efficient and simple way, the PHY and MAC information present the key elements of the aimed resource allocation. Simulation results demonstrate that the proposed scheme provides a good tradeoff between the QoS satisfaction of the unlicensed applications with hard QoS requirements and the limitation of the interference affecting the licensed users.
Cross-Layer Resource Allocation Scheme Under Heterogeneous Constraints for Next Generation High Rate WPAN  [PDF]
Ayman Khalil,Matthieu Crussière,Jean-Fran?ois Hélard
International Journal of Computer Networks & Communications , 2010,
Abstract: In the next generation wireless networks, the growing demand for new wireless applications isaccompanied with high expectations for better quality of service (QoS) fulfillment especially formultimedia applications. Furthermore, the coexistence of future unlicensed users with existing licensedusers is becoming a challenging task in the next generation communication systems to overcome theunderutilization of the spectrum. A QoS and interference aware resource allocation is thus of specialinterest in order to respond to the heterogeneous constraints of the next generation networks. In thiswork, we address the issue of resource allocation under heterogeneous constraints for unlicensed multibandultra-wideband (UWB) systems in the context of Future Home Networks, i.e. the wireless personalarea network (WPAN). The problem is first studied analytically using a heterogeneous constrainedoptimization problem formulation. After studying the characteristics of the optimal solution, we propose alow-complexity suboptimal algorithm based on a cross-layer approach that combines informationprovided by the PHY and MAC layers. While the PHY layer is responsible for providing the channelquality of the unlicensed UWB users as well as their interference power that they cause on licensed users,the MAC layer is responsible for classifying the unlicensed users using a two-class based approach thatguarantees for multimedia services a high-priority level compared to other services. Combined in anefficient and simple way, the PHY and MAC information present the key elements of the aimed resourceallocation. Simulation results demonstrate that the proposed scheme provides a good tradeoff betweenthe QoS satisfaction of the unlicensed applications with hard QoS requirements and the limitation of theinterference affecting the licensed users.
CROSS-LAYER RESOURCE ALLOCATION SCHEME UNDER HETEROGENEOUS CONSTRAINTS FOR NEXT GENERATION HIGH RATE WPAN  [PDF]
Ayman Khalil,Matthieu Crussiere,Jean-Francois Helard
International Journal of Network Security & Its Applications , 2010,
Abstract: In the next generation wireless networks, the growing demand for new wireless applications isaccompanied with high expectations for better quality of service (QoS) fulfillment especially formultimedia applications. Furthermore, the coexistence of future unlicensed users with existing licensedusers is becoming a challenging task in the next generation communication systems to overcome theunderutilization of the spectrum. A QoS and interference aware resource allocation is thus of specialinterest in order to respond to the heterogeneous constraints of the next generation networks. In thiswork, we address the issue of resource allocation under heterogeneous constraints for unlicensed multibandultra-wideband (UWB) systems in the context of Future Home Networks, i.e. the wireless personalarea network (WPAN). The problem is first studied analytically using a heterogeneous constrainedoptimization problem formulation. After studying the characteristics of the optimal solution, we propose alow-complexity suboptimal algorithm based on a cross-layer approach that combines informationprovided by the PHY and MAC layers. While the PHY layer is responsible for providing the channelquality of the unlicensed UWB users as well as their interference power that they cause on licensed users,the MAC layer is responsible for classifying the unlicensed users using a two-class based approach thatguarantees for multimedia services a high-priority level compared to other services. Combined in anefficient and simple way, the PHY and MAC information present the key elements of the aimed resourceallocation. Simulation results demonstrate that the proposed scheme provides a good tradeoff betweenthe QoS satisfaction of the unlicensed applications with hard QoS requirements and the limitation of theinterference affecting the licensed users.
Coexistence of Wi-Fi and Heterogeneous Small Cell Networks Sharing Unlicensed Spectrum  [PDF]
Haijun Zhang,Xiaoli Chu,Weisi Guo,Siyi Wang
Mathematics , 2015,
Abstract: As two major players in terrestrial wireless communications, Wi-Fi systems and cellular networks have different origins and have largely evolved separately. Motivated by the exponentially increasing wireless data demand, cellular networks are evolving towards a heterogeneous and small cell network architecture, wherein small cells are expected to provide very high capacity. However, due to the limited licensed spectrum for cellular networks, any effort to achieve capacity growth through network densification will face the challenge of severe inter-cell interference. In view of this, recent standardization developments have started to consider the opportunities for cellular networks to use the unlicensed spectrum bands, including the 2.4 GHz and 5 GHz bands that are currently used by Wi-Fi, Zigbee and some other communication systems. In this article, we look into the coexistence of Wi-Fi and 4G cellular networks sharing the unlicensed spectrum. We introduce a network architecture where small cells use the same unlicensed spectrum that Wi-Fi systems operate in without affecting the performance of Wi-Fi systems. We present an almost blank subframe (ABS) scheme without priority to mitigate the co-channel interference from small cells to Wi-Fi systems, and propose an interference avoidance scheme based on small cells estimating the density of nearby Wi-Fi access points to facilitate their coexistence while sharing the same unlicensed spectrum. Simulation results show that the proposed network architecture and interference avoidance schemes can significantly increase the capacity of 4G heterogeneous cellular networks while maintaining the service quality of Wi-Fi systems.
Energy-Efficient 5G Outdoor-to-Indoor Communication: SUDAS Over Licensed and Unlicensed Spectrum  [PDF]
Derrick Wing Kwan Ng,Marco Breiling,Christian Rohde,Frank Burkhardt,Robert Schober
Mathematics , 2015,
Abstract: In this paper, we study the joint resource allocation algorithm design for downlink and uplink multicarrier transmission assisted by a shared user equipment (UE)-side distributed antenna system (SUDAS). The proposed SUDAS simultaneously utilizes licensed frequency bands and unlicensed frequency bands, (e.g. millimeter wave bands), to enable a spatial multiplexing gain for single-antenna UEs to improve energy efficiency and system throughput of $5$-th generation (5G) outdoor-to-indoor communication. The design of the UE selection, the time allocation to uplink and downlink, and the transceiver processing matrix is formulated as a non-convex optimization problem for the maximization of the end-to-end system energy efficiency (bits/Joule). The proposed problem formulation takes into account minimum data rate requirements for delay sensitive UEs and the circuit power consumption of all transceivers. In order to design a tractable resource allocation algorithm, we first show that the optimal transmitter precoding and receiver post-processing matrices jointly diagonalize the end-to-end communication channel for both downlink and uplink communication via SUDAS. Subsequently, the matrix optimization problem is converted to an equivalent scalar optimization problem for multiple parallel channels, which is solved by an asymptotically globally optimal iterative algorithm. Besides, we propose a suboptimal algorithm which finds a locally optimal solution of the non-convex optimization problem. Simulation results illustrate that the proposed resource allocation algorithms for SUDAS achieve a significant performance gain in terms of system energy efficiency and spectral efficiency compared to conventional baseline systems by offering multiple parallel data streams for single-antenna UEs.
Spectrum Sharing in a Long Term Spectrum Strategy via Cognitive Radio for Heterogeneous Wireless Networks
R.Kaniezhil,Dr. C. Chandrasekar
International Journal on Computer Science and Engineering , 2012,
Abstract: In this paper, Spectrum sharing technique among service providers to share the licensed spectrum of the licensed service providers for Heterogeneous wireless networks in a dynamic manner is proposed. Here, we could analyze and sense out the unoccupied bands, free bands, allocated bands by calculating the free spectrum metric. Hence, providing the opportunistic access to the licensed spectrum for unlicensed users ie other service providers try to access the available spectrum without causing interference to the primary users.
Worst-Case Robust Distributed Power Allocation in Shared Unlicensed Spectrum  [PDF]
Saeideh Parsaei fard,Ahmad R. Sharafat
Mathematics , 2011,
Abstract: This paper considers non-cooperative and fully-distributed power-allocation for selfish transmitter-receiver pairs in shared unlicensed spectrum when normalized-interference to each receiver is uncertain. We model each uncertain parameter by the sum of its nominal (estimated) value and a bounded additive error in a convex set, and show that the allocated power always converges to its equilibrium, called robust Nash equilibrium (RNE). In the case of a bounded and symmetric uncertainty region, we show that the power allocation problem for each user is simplified, and can be solved in a distributed manner. We derive the conditions for RNE's uniqueness and for convergence of the distributed algorithm; and show that the total throughput (social utility) is less than that at NE when RNE is unique. We also show that for multiple RNEs, the social utility may be higher at a RNE as compared to that at the corresponding NE, and demonstrate that this is caused by users' orthogonal utilization of bandwidth at RNE. Simulations confirm our analysis.
Traffic-Driven Spectrum Allocation in Heterogeneous Networks  [PDF]
Binnan Zhuang,Dongning Guo,Michael L. Honig
Mathematics , 2014,
Abstract: Next generation cellular networks will be heterogeneous with dense deployment of small cells in order to deliver high data rate per unit area. Traffic variations are more pronounced in a small cell, which in turn lead to more dynamic interference to other cells. It is crucial to adapt radio resource management to traffic conditions in such a heterogeneous network (HetNet). This paper studies the optimization of spectrum allocation in HetNets on a relatively slow timescale based on average traffic and channel conditions (typically over seconds or minutes). Specifically, in a cluster with $n$ base transceiver stations (BTSs), the optimal partition of the spectrum into $2^n$ segments is determined, corresponding to all possible spectrum reuse patterns in the downlink. Each BTS's traffic is modeled using a queue with Poisson arrivals, the service rate of which is a linear function of the combined bandwidth of all assigned spectrum segments. With the system average packet sojourn time as the objective, a convex optimization problem is first formulated, where it is shown that the optimal allocation divides the spectrum into at most $n$ segments. A second, refined model is then proposed to address queue interactions due to interference, where the corresponding optimal allocation problem admits an efficient suboptimal solution. Both allocation schemes attain the entire throughput region of a given network. Simulation results show the two schemes perform similarly in the heavy-traffic regime, in which case they significantly outperform both the orthogonal allocation and the full-frequency-reuse allocation. The refined allocation shows the best performance under all traffic conditions.
Structured Spectrum Allocation and User Association in Heterogeneous Cellular Networks  [PDF]
Wei Bao,Ben Liang
Computer Science , 2013,
Abstract: We study joint spectrum allocation and user association in heterogeneous cellular networks with multiple tiers of base stations. A stochastic geometric approach is applied as the basis to derive the average downlink user data rate in a closed-form expression. Then, the expression is employed as the objective function in jointly optimizing spectrum allocation and user association, which is of non-convex programming in nature. A computationally efficient Structured Spectrum Allocation and User Association (SSAUA) approach is proposed, solving the optimization problem optimally when the density of users is low, and near-optimally with a guaranteed performance bound when the density of users is high. A Surcharge Pricing Scheme (SPS) is also presented, such that the designed association bias values can be achieved in Nash equilibrium. Simulations and numerical studies are conducted to validate the accuracy and efficiency of the proposed SSAUA approach and SPS.
A Harmful Interference Model for Unlicensed Device Operation in Licensed service Bands  [cached]
Timothy X Brown
Journal of Communications , 2006, DOI: 10.4304/jcm.1.1.13-25
Abstract: Recent FCC proceedings have considered the notion of unlicensed device operation in licensed bands. Licensed users are concerned about harmful interference while unlicensed device manufacturers are concerned that harmful interference is an imprecise design concept. This paper addresses two elements to these concerns. First, it develops an explicit model of harmful interference to be included in unlicensed device rules. Such a model provides explicit bounded protection to the licensed user while providing assurances and performance goals to the unlicenseddevice manufacturers. Second, it presents an analytic model for assessing harmful interference that not only provides quantitative analysis, but, also provides insight into how factors such as directional antennas, power control, and licensed channel avoidance strategies affect the aggregate interference. Further, it suggests that complex factors such as unlicensed device modulation schemes can be captured in a simple measurement. These ideas are applied to the notice of proposed rulemaking on Unlicensed Operation in the TV Broadcast Bands.
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