Self organization of tilts in relay enhanced networks: a distributed solution

Despite years of physical-layer research, the capacity enhancement potential of relays is limited by the additional spectrum required for Base Station (BS)-Relay Station (RS) links. This paper presents a novel distributed solution by exploiting a system level perspective instead. Building on a realistic system model with impromptu RS deployments, we develop an analytical framework for tilt optimization that can dynamically maximize spectral efficiency of both the BS-RS and BS-user links in an online manner. To obtain a distributed self-organizing solution, the large scale system-wide optimization problem is decomposed into local small scale subproblems by applying the design principles of self-organization in biological systems. The local subproblems are non-convex, but having a very small scale, can be solved via standard nonlinear optimization techniques such as sequential quadratic programming. The performance of the developed solution is evaluated through extensive simulations for an LTE-A type system and compared against a number of benchmarks including a centralized solution obtained via brute force, that also gives an upper bound to assess the optimality gap. Results show that the proposed solution can enhance average spectral efficiency by up to 50% compared to fixed tilting, with negligible signaling overheads. The key advantage of the proposed solution is its potential for autonomous and distributed implementation

Optimizing Umts Radio Coverage Via Base Station Configuration

Due to the W-CDMA radio interface, the area covered by a set of UMTS base stations depends on the signal quality requirements, the power control mechanism as well as on the traffic distribution. In previous work we have proposed discrete optimization models and algorithms for locating base stations in UMTS networks. In this paper we address the general problem of optimizing base station locations as well as their configurations, such as antenna height, tilt, and sector orientation. The proposed model, which can also be used to only optimize the base station configurations, accounts for the power control mechanism typical of W-CDMA an considers the Signal-to-Interference Ratio (SIR) as quality measure. To find good approximate solutions of this NP-hard problem, we develop a Tabu Search algorithm which takes into account traffic coverage and installation costs. Experimental results showing the effect of considering base station configurations in the planning process are reported

Netted radar modelling, design and optimisation

Networks of phased array radars are able to provide better counter stealth target detection and classification. Each radar sensor/node generates information which requires transmission to a central control authority who is able to evaluate the information. This requires a communications network to be established to allow transmission of information to and from any node. Each radar node is limited by range and degree and relies on the formation of a multi-hop network to facilitate this transmission. This thesis investigates a method whereby the radar beam itself is used in the formation of a multi-hop network. The phased array's multifunctional nature allows rapid switching between communications and radar function. A complete model of how the communication system could operate is included in this thesis. In order to simulate radar function and network communication, a custom built simulation platform was used. Two different approaches to the formation of the radar networks are derived, one involving a global design method using the Strength Pareto Evolutionary Algorithm (SPEA) and another using a local method specifically tailored to radar network formation, Distributed Algorithm for Radar Topology Control (DARTC). Both of these techniques can be used in the formation of radar networks. The thesis goes further to suggest modifications to the model itself that could result in improved radar network communication performance.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Netted radar modelling, design and optimisation

Networks of phased array radars are able to provide better counter stealth target detection and classification. Each radar sensor/node generates information which requires transmission to a central control authority who is able to evaluate the information. This requires a communications network to be established to allow transmission of information to and from any node. Each radar node is limited by range and degree and relies on the formation of a multi-hop network to facilitate this transmission. This thesis investigates a method whereby the radar beam itself is used in the formation of a multi-hop network. The phased array's multifunctional nature allows rapid switching between communications and radar function. A complete model of how the communication system could operate is included in this thesis. In order to simulate radar function and network communication, a custom built simulation platform was used. Two different approaches to the formation of the radar networks are derived, one involving a global design method using the Strength Pareto Evolutionary Algorithm (SPEA) and another using a local method specifically tailored to radar network formation, Distributed Algorithm for Radar Topology Control (DARTC). Both of these techniques can be used in the formation of radar networks. The thesis goes further to suggest modifications to the model itself that could result in improved radar network communication performance