Research Of Self-Healing In Heterogeneous Network

To enhance the capacity and meet the demand of deep coverage, the heterogeneous deployment has been emerged in the LTE-Advanced system, where the system gains are only achievable through deployment of low-power nodes. The modern wireless communication system is becoming increasingly complicated with its requirement for high throughput, seamless coverage and ubiquitous feature. Maintaining the intricate network at a properly working state by traditional approaches is rather time-consuming and costly. In order to overcome problems related to reduce capital and operational expenditures and to improve system performance, the self-organizing networks (SON) is introduced and promoted, which owns the ability to configure, optimize and heal itself automatically. The configuration and maintenance of network devices and parameters makes network management become more complicated, and the reasonable solutions to detection and automatic repair of network breakdown will be both tough and urgent. LTE-Advanced self-healing function emerges, which can detect and locate the network defaults automatically, promptly and correctly by processing the network monitoring statistics. It can also recover or compensate for the breakdown to insure the high consistency and quality of communication for users. This article introduces the outage detection and compensation function with their own corresponding solutions which have been simulated respectively to validate their rationality and efficiency.In the first point, we present a cell outage detection mechanism for discovering network failures automatically in future mobile wireless system. On the basis of network measurements from UEs, eNodeBs and OAM, the proposed approach named Dynamic Affinity Propagation algorithm has been implemented successfully in LTE-Advanced simulation environment. Finally, the user position information is employed to map clustering results into network topology through which we can make a clearly decision that there are two outages during current monitoring period and further locate the specific outage areas at the same time. Then, the proposed mechanism is further extended to be employed in heterogeneous networks for fault detection based on collected key performance measurementsIn the second point, we present a cell outage compensation mechanism to minimize network performance degradation automatically after a macrocell outage being detected in heterogeneous networks. Picocells configured at the faulty area will allocate RBs using the intrinsic spectrum resources of macrocells to outage users. Then the Lagrange function is employed to optimize the power reallocation of each user to maximize each picocell’s throughput. A parameter of the resource allocation algorithm named "compensation timeslot" is introduced to mitigate the interference of outage macro users by turning down the data transmission of surrounding macro cells during compensation timeslot. The outage macro users can get satisfying service after compensation while the macro user served by surrounding macro cells will be slightly influenced. Also, the tradeoff between the serving quality of these two kinds of users can be easily controlled by adjusting the proportion of compensation timeslot.