Andreas Bergström

Performance of WLAN RSS-based SON for LTE/WLAN access network selection

Mobile Network Operators (MNOs) are integrating carrier-grade Wireless Local Area Network (WLAN) to cellular networks to improve network performance and user experience. Access network selection (ANS) between cellular and WLAN plays a key role in the integration. Given the complexity of heterogeneous networks characterized by multiple network layer deployments and inhomogeneous traffic distribution, the ANS has to automatically adapt to dynamic network conditions. In this article, we present and evaluate a Self-Organizing Network (SON) algorithm for tuning the ANS between the Long Term Evolution (LTE) and WLAN systems. The proposed SON algorithm adopts a WLAN received signal strength (RSS) threshold to control the access selection. The RSS threshold is updated by the SON algorithm based on periodically monitored load in the LTE and WLAN systems. The SON algorithm is evaluated by simulations in realistic heterogeneous network scenarios and proved effective in improving user experience.

Improved Latency Performance with GSM/EDGE Continued Evolution

The worlds largest and most widespread cellular technology today is GSM/EDGE. EDGE is capable of offering an attractive solution for 3rd generation cellular services in existing GSM networks. However, the introduction of new and more delay sensitive services may require improved latency performance. Reducing the delay and increasing the bandwidth efficiency in EDGE systems is important for services with stringent latency requirements, such as conversational VoIP, but will be beneficial also to other services. Proposed is to reduce the transmission time interval from 20 ms to 10 ms, in combination with novel procedures for faster feedback. Simulation results show that LLC delays may be reduced by 20-40% depending on traffic scenario. Furthermore, channel resource requirements for VoIP could be substantially reduced.

Retransmission Schemes for 5G Radio Interface

The standardization of 5G radio interface has started in 3GPP since April 2016. For the design of retransmission schemes, some requirements such as flexible timing, low overhead, and fast feedback have already been identified. Considering these design requirements, the retransmission mechanisms for single-hop and multi-hop 5G scenarios are presented in this paper. A novel protocol for the HARQ/ARQ is proposed, that is designed to be not only fast and low-overhead but also reliable and does not require fixed timing relationships. Several RLC ARQ protocol architectures are also analysed for the multihop/self-backhaul scenarios. The results demonstrate that relay RLC protocol is a promising candidate for multi-hop scenarios.