15,718 research outputs found
Optimal channel allocation with dynamic power control in cellular networks
Techniques for channel allocation in cellular networks have been an area of
intense research interest for many years. An efficient channel allocation
scheme can significantly reduce call-blocking and calldropping probabilities.
Another important issue is to effectively manage the power requirements for
communication. An efficient power control strategy leads to reduced power
consumption and improved signal quality. In this paper, we present a novel
integer linear program (ILP) formulation that jointly optimizes channel
allocation and power control for incoming calls, based on the
carrier-to-interference ratio (CIR). In our approach we use a hybrid channel
assignment scheme, where an incoming call is admitted only if a suitable
channel is found such that the CIR of all ongoing calls on that channel, as
well as that of the new call, will be above a specified value. Our formulation
also guarantees that the overall power requirement for the selected channel
will be minimized as much as possible and that no ongoing calls will be dropped
as a result of admitting the new call. We have run simulations on a benchmark
49 cell environment with 70 channels to investigate the effect of different
parameters such as the desired CIR. The results indicate that our approach
leads to significant improvements over existing techniques.Comment: 11 page
Hybrid Spectrum Allocation Scheme in Wireless Cellular Networks
Mobile services have seen a major upswing driven by the bandwidth hungry applications thus leading to higher data rate requirements on the wireless networks. Spectrum being the most precious resource in the wireless industry is of keen interest. Various spectrum assignment and frequency reuse schemes have been proposed in literature. However in future networks, dynamic schemes that adapt to spatio-temporal variation in the environment are desired. We thus present a hybrid spectrum assignment scheme which adapts its allocation strategies depending on user distribution in the system. Results show that the proposed dynamic spectrum assignment strategy improves spectrum utilization thereby providing a higher data rate for the users
A cross-layer heuristic algorithm for addressing shadowing problem in optical attocell networks
The performance of visible light communication (VLC)-based optical attocell networks degrades due to shadowing caused by opaque objects. In order to improve reliability, we propose a cross-layer algorithm to find the optimal routing and resource allocation schemes when shadowing occurs. Simulation results show that the optimal scheme found by the proposed algorithm significantly improves the performance of optical attocell networks with one randomly shadowed link
A survey on OFDM-based elastic core optical networking
Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed
Joint Dynamic Radio Resource Allocation and Mobility Load Balancing in 3GPP LTE Multi-Cell Network
Load imbalance, together with inefficient utilization of system resource, constitute major factors responsible for poor overall performance in Long Term Evolution (LTE) network. In this paper, a novel scheme of joint dynamic resource allocation and load balancing is proposed to achieve a balanced performance improvement in 3rd Generation Partnership Project (3GPP) LTE Self-Organizing Networks (SON). The new method which aims at maximizing network resource efficiency subject to inter-cell interference and intra-cell resource constraints is implemented in two steps. In the first step, an efficient resource allocation, including user scheduling and power assignment, is conducted in a distributed manner to serve as many users in the whole network as possible. In the second step, based on the resource allocation scheme, the optimization objective namely network resource efficiency can be calculated and load balancing is implemented by switching the user that can maximize the objective function. Lagrange Multipliers method and heuristic algorithm are used to resolve the formulated optimization problem. Simulation results show that our algorithm achieves better performance in terms of user throughput, fairness, load balancing index and unsatisfied user number compared with the traditional approach which takes resource allocation and load balancing into account, respectively
A Comprehensive Survey of Potential Game Approaches to Wireless Networks
Potential games form a class of non-cooperative games where unilateral
improvement dynamics are guaranteed to converge in many practical cases. The
potential game approach has been applied to a wide range of wireless network
problems, particularly to a variety of channel assignment problems. In this
paper, the properties of potential games are introduced, and games in wireless
networks that have been proven to be potential games are comprehensively
discussed.Comment: 44 pages, 6 figures, to appear in IEICE Transactions on
Communications, vol. E98-B, no. 9, Sept. 201
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