Yapeng Wang

Bluetooth positioning using RSSI and triangulation methods

Location based services are the hottest applications on mobile devices nowadays and the growth is continuing. Indoor wireless positioning is the key technology to enable location based services to work well indoors, where GPS normally could not work. Bluetooth has been widely used in mobile devices like phone, PAD etc. therefore Bluetooth based indoor positioning has great market potential. Radio Signal Strength (RSS) is a key parameter for wireless positioning. New Bluetooth standard (since version 2.1) enables RSS to be discovered without time consuming pre-connection. In this research, general wireless positioning technologies are firstly analysed. Then RSS based Bluetooth positioning using the new feature is studied. The mathematical model is established to analyse the relation between RSS and the distance between two Bluetooth devices. Three distance-based algorithms are used for Bluetooth positioning: Least Square Estimation, Three-border and Centroid Method. Comparison results are analysed and the ways to improve the positioning accuracy are discussed.

Intelligent radio resource management for IEEE 802.11 WLAN

IEEE 802.11 based WLANs have been widely deployed. Currently research is concentrating on how to find the best location for these access points plus tuning their antennas in order to seamlessly cover large areas. With more and more WLAN users, the air interface acts as bottleneck even in high-speed WLAN systems such as IEEE 802.11a. To improve the overall performance of IEEE 802.11 WLAN systems under congestion conditions, an agent-based radio resource management system is proposed that can dynamically change an APs radio coverage pattern in cooperation with surrounding APs. A low-cost four sector semismart antenna array is used for access points. In this paper we present results from a simulation showing system performance. The use of intelligent agents and negotiations for indoor radio resource management is presented and discussed.

Resource Allocation in LTE OFDMA Systems Using Genetic Algorithm and Semi-Smart Antennas

Orthogonal frequency division multiplexing (OFDMA) offers great spectrum efficiency and flexible frequency allocation to users without intra-cell interferences in LTE system. However, the cell edge users will experience high interferences from neighbouring cells. Many frequency reuse schemes have been proposed for improving the Signal to Interference and Noise Ratio (SINR) performance for cell edge users, most of them dividing available frequencies into groups for cell centre and cell edge users. In this research, we combine the traditional frequency scheme with novel semi-smart antennas and learning algorithm - Genetic Algorithm (GA). The semi-smart antennas can produce flexible coverage patterns for base stations (BSs) and the learning algorithm can coordinate the coverage patterns between BSs to minimise interferences for mobile units (MUs). A system level simulation contains 25 BSs and 1000 MUs has been developed. Simulation results show that the proposed scheme improves the total traffic load and reduces antenna propagation power for all cells compares to system with fixed coverage patterns.

Stacked Patch Antenna With Dual-Polarization and Low Mutual Coupling for Massive MIMO

Massive multiple input and multiple output (MIMO) has attracted significant interests in both academia and industry. It has been considered as one of most promising technologies for 5G wireless systems. The large-scale antenna array for base stations naturally becomes the key to deploy the Massive MIMO technologies. In this communication, we present a dual-polarized antenna array with 144 ports for Massive MIMO operating at 3.7 GHz. The proposed array consists of 18 low profile subarrays. Each subarray consists of four single units. Each single antenna unit consists of one vertically polarized port and one horizontally polarized port connected to power splitters, which serve as a feeding network. A stacked patch design is used to construct the single unit with the feeding network, which gives higher gain and lower mutual coupling within the size of a conversional dual-port patch antenna. Simulation results of the proposed single antenna unit, sub-array, and Massive MIMO array are verified by measurement.

Intelligent Control Of Cellular Network Coverage Using Semi-Smart Antennas For Load Balancing

This paper examines the issues of traffic load balancing in wideband code division multiple access (WCDMA) mobile communication networks through applying dynamic radio coverage. Dynamic radio coverage is achieved by adjusting radiation patterns of antenna arrays and the optimization of coverage is carried out cooperatively between cells using dedicatedly designed algorithm. In comparison with previous work, the discussion starts at how to apply the method to richer models, where propagation effect due to terrain is present A mapping process is therefore introduced to build traffic pattern using path loss information instead of using geographic locations. The paper then goes on to examine the mechanisms involved in the shaping of radiation patterns for a linear array. Finally, simulation results are used to examine the system level performance of a network employing cooperative coverage.

QoS-aware radio resource allocation for multi-cell OFDMA network

This paper provides a new approach allocating resources between multimedia users in a multi-cell OFDMA system in order to maximize the number of users that can achieve their QoS requirements. It does this by formulating the problem as a non-cooperative game. We propose a distributed algorithm to get the Nash equilibrium (NE) as well as introducing a new performance indicator (the qualified throughput) to measure the actual throughput gained by those users whose QoS requirement is met. The proposed algorithm can achieve fast convergence and enhanced performance; it can also efficiently deal with an unbalanced user distribution as well as with a uniform one. In this paper we also validate the algorithm by using Iterative Water Filling (IWF) as a benchmark and compare it with an existing algorithm. It can offer significant advantages and successfully handle a mix of QoS requirements between users. The approach is generic but in the paper is applied to the uplink in a scenario based on IEEE802.22 Cognitive Radio.

Intelligent resource optimisation using semi-smart antennas in LTE OFDMA systems

The next generation 3GPP long-term evolution (LTE) mobile system will use orthogonal frequency division multiplexing access (OFDMA) as the key technology to improve the spectrum efficiency and flexible user resource allocation. One of the challenges of OFDMA systems is the interference at the cell edge where users are likely to get high interference from neighbouring cells. In a network with non-uniform traffic distribution, the problem becomes even more challenging. In this paper, a semi-smart antenna based resource allocation scheme is proposed for the LTE OFDMA system. The scheme features a centralised Genetic Algorithm (GA) algorithm that changes the cellular coverage in a coordinated manner to improve the system capacity and mitigate network interference. Simulation experiments have been carried out to evaluate the performance of the proposed scheme, the results showing significant performance improvement in terms of total traffic load achieved for all cells compared to a system with fixed coverage pattern.

Circular co-planar inverted-F antenna for UHF Machine-to-Machine communications

A circular co-planar inverted-F antenna (CCIFA) for UHF Machine-to-Machine (M2M) communications is presented and analyzed in this paper. The proposed antenna is designed with a common PCB with only one metal layer forming a ring and disk with a radius of less than 0.1λ. An optimized design operating at 480MHz with a radius of 33mm is analyzed. The performance of the antenna is compared with existing reference antennas.

An Intelligent Context-Aware Spatial Routing System in Mobile Environment

The rapid growth and development of wireless communication and networking technologies coupled with far more powerful and energy efficient mobile computing systems enable more intelligent behaviours such as user-centric and self-reflection to be used so that mobile user applications can leverage dynamic context information to provide customized services. In this research, an architectural model for the deployment of intelligent context-aware service adaptation process is introduced. A mobile spatial routing application is exploited to demonstrate the improved flexibility and robustness of the new system model.

Blue Danger: Live Action Gaming Over Bluetooth

A community live action game over Bluetooth, namely Blue Danger, is proposed in this paper. The market penetration of Bluetooth provides an excellent media for such game in which a large number of players is required. Bluetooth has a relatively short transmission range that allows a dynamic mobile adhoc network environment to be created which is ideal for the action game proposed. In addition, reliability of Bluetooth as well as its detection and tracking have been examined during the development of the game. A prototype game framework has been built and tested.