Lexi Xu

Mobility load balancing aware radio resource allocation scheme for LTE-Advanced cellular networks

Mobility load balancing (MLB) is widely used to address the uneven load distribution problem. The basic idea is that a hot-spot cell selects less-loaded neighbouring cells as assistant cells, and thenshiftsitsedge users to assistant cells via the handover region adjustment. However, shifted users receive the reduced signal power after MLB, which may result in the poor link quality problem for shifted users. In order to deal with this problem, this paper proposes a mobility load balancing aware radio resource allocation (MLBRRA) scheme. In the MLBRRA scheme, the assistant cell jointly considers the MLB factor of the shifted user and that of the hot-spot cell, as well as the proportional fairness scheduling factor. More specifically, the assistant cell preferentially allocates radio resources to shifted users, which are suffering poor link quality or previously served by a hot-spot cell with large handover region. Simulation results show that the proposed MLBRRA scheme can effectively deal with the poor link quality problem in terms of handover failure and call dropping. The proposed scheme can also reduce the call blocking probability.

Self-organizing Load Balancing for Relay Based Cellular Networks

A self-organizing load balancing framework is proposed in this paper. It provides self-optimizing load balancing policies to improve adaptation and robustness of Fixed Relay Station (FRS) based cellular networks. The framework proposes a Self-organizing Cooperative Partner Cluster (SCPC) concept to dynamically select optimal partners of each BS and RS. A novel Comprehensive Load Balancing Policy Stack (CLBPS) is also proposed to utilize merits of various load balancing policies. Load balancing performance, signaling costs and user experience are taken into account in both SCPC and CLBPS. Simulation results show that the call blocking rate is reduced and the network throughput of FRS networks is improved.

Self-optimised Coordinated Traffic Shifting Scheme for LTE Cellular Systems

Mobility load balancing is widely used in LTE cellular systems to deal with the uneven load distribution. Its basic idea is to shift traffic from a hot-spot cell to less-loaded neighbouring cells, called partners. Conventional schemes focus on the hot-spot cell’s load reduction and pay less attention to the performance of partners. This paper proposes a self-optimised coordinated traffic shifting scheme. In the proposed scheme, the coordination among partners is considered. Meanwhile, the shifted traffic is adjusted dynamically according to the load balancing (LB) performance. Simulation results show the proposed scheme can keep low call blocking probability of partners. It can also keep the number of Ping-Pong LB and the LB handover dropping probability at low levels.

User-vote assisted self-organizing load balancing for OFDMA cellular systems

Load balancing (LB) is an important function of the self-organizing network (SON) for coping with the uneven load distribution to achieve higher spectrum efficiency and lower operational expenditure. This paper proposes a cluster based self-organizing LB scheme, which employs a user-vote mechanism to avoid the ‘virtual partner’ problem experienced by current LB schemes with the load-based partner selection. The user-vote can assist the hot-spot base station (BS) to efficiently select partner BSs for constructing its cluster, and then shift the traffic to the partners within the cluster. Simulation results show that the proposed scheme can effectively solve the ‘virtual partner’ problem. Furthermore, it can reduce the call blocking rate via a small number of partner BSs.

Telecom Big Data Based User Offloading Self-Optimisation in Heterogeneous Relay Cellular Systems

This paper proposes a telecom big data based user offloading self-optimisation TBDUOS scheme. Its aim is to assist telecom operators to effectively balancing the load distribution with achieving good service performance and customer management in heterogeneous relay cellular systems. To achieve these objectives, in the cell-level offloaded traffic analysis stage, the optimal offloaded traffic is calculated to minimise the total blocking probability. In the user-level offloading stage, the user portrait is drawn and the K-MEANS algorithm is employed to manage the users clustering in the heavily loaded cell, and finally shifting users to assistant cells. Simulation results show the TBDUOS scheme can effectively reduce the handover failure and call dropping of specific users, especially voice/stream users, high consumption users, high level users. The TBDUOS scheme can also reduce the blocking probability.

Self-optimised joint traffic offloading in heterogeneous cellular networks

Traffic offloading is a widely used technique to address the unbalanced traffic distribution between pico cells and macro cells in heterogeneous cellular networks. However, the shifted users may result in the macro cell receiving large traffic from multiple pico cells and then becoming heavily loaded. This phenomenon is called the exacerbation problem in this paper. In order to address this problem and balance load effectively, this paper proposes a self-optimised joint traffic offloading (JTO) scheme. The JTO scheme jointly employs two traffic offloading techniques, including cell biasing technique to offload traffic between pico cell and macro cell, and mobility load balancing among macro cells. Simulation results show the JTO scheme can effectively deal with the cell exacerbation problem, in terms of handover failure and call dropping. The JTO scheme can also reduce the call blocking probability.

User Relay Assisted Traffic Shifting in LTE-Advanced Systems

In order to deal with uneven load distribution, mobility load balancing adjusts the handover region to shift edge users from a hot-spot cell to the less-loaded neighbouring cells. However, shifted users receive the reduced signal power from neighbouring cells, which may result in link quality degradation. This paper employs a user relaying model and proposes a user relay assisted traffic shifting (URTS) scheme to address this problem. In URTS scheme, a shifted user selects a suitable non-active user as relay user to forward signal, thus enhancing the link quality of the shifted user. Since the user relaying model consumes relay users energy, a utility function is designed in relay selection to reach a trade-off between the shifted users link quality improvement and the relay users energy consumption. Simulation results show that the URTS scheme can improve SINR and capacity of shifted users. Also, URTS scheme keeps the cost of relay users energy consumption at an acceptable level.

A survey of security and privacy in big data

Big data has been arising a growing interest in both scientific and industrial fields for its potential value. However, before employing big data technology into massive applications, a basic but also principle topic should be investigated: security and privacy. In this paper, the recent research and development on security and privacy in big data is surveyed. First, the effects of characteristics of big data on information security and privacy are described. Then, topics and issues on security are discussed and reviewed. Further, privacy-preserving trajectory data publishing is studied due to its future utilization, especially in telecom operation.

A novel power control mechanism based on interference estimation in LTE cellular networks

In LTE cellular networks, the pathloss impacts the performance of the uplink channel power control. Therefore, power control algorithms can achieve good performance on the location where user equipment (UE) is not power limited. The baseline parameter setting of the fractional pathloss power control is valid for some scenarios, however, it is a challenging issue to improve the cell edge throughput in the complex environment, especially the mix of indoor and outdoor UE scenario. This paper proposes a novel interference based power control mechanism. The key is to estimate the interference generated by UEs to other cells. Simulation results show that the proposed mechanism can effectively improve the throughput for UEs with high pathloss. In addition, the proposed mechanism can also reduce the interference from other UEs with low pathloss.

Priority-based resource allocation to Guarantee Handover and Mitigate Interference for OFDMA system

Mitigating Inter-cell Interference (ICI) and ensuring seamless high-quality communication are two challenging issues for OFDMA systems. Cell-level coordinated resource allocation and handover (HO) are the two key technologies for achieving these goals. They have been investigated intensively, however, mainly separately. In this paper, a novel combined Handover Guarantee and Interference Mitigation (HGIM) cell-level resource allocation scheme is proposed. HGIM defines the Handover User Set (HUS) and grants higher allocation priority to handover users. Other active users are prioritized based on a unified cell division model which divides a cell into different ICI sensitive areas. Meanwhile, HGIM defines a Sub-carrier Preferred List (SPL) to optimize allocation. Simulation results show that HGIM achieves greater ICI mitigation and improved handover performance compared with the conventional soft frequency reuse scheme.