A real-time performance evaluation of tightly coupled LTE Wi-Fi radio access networks

Abstract

A tight coupling of LTE and Wi-Fi interfaces can be achieved by integrating them at their radio protocol stacks. LTE and Wi-Fi radio level integration with IPSec tunnel (LWIP) was introduced by 3GPP as part of Rel-13. This tighter level of interworking replaces the traditional way of cellular-Wi-Fi interworking through a packet gateway and it can react to the dynamic changes in the wireless link quality. In this paper, we present a variant of LWIP prototype that works with commercial UE (Nexus 5). The developed LWIP prototype uses OpenAirInterface (OAI) for LTE network and Cisco Access Point (AP) as Wi-Fi AP. We also present the design and implementation of LWIP prototype and interesting results for tight interworking of LTE and Wi-Fi at IP level. We have evaluated the LWIP performance with different Link Aggregation Strategies (LAS) using both UDP and TCP. We have observed that, in a highly loaded Wi-Fi channel, when LWIP employs Wi-Fi only in Downlink (WoD) LAS, then sum of individual TCP flow throughput has improved by 28% as compared to LWIP operating with Flow Split (FS) LAS. We have enumerated the challenges which has to be addressed in LWIP to reap the maximum benefits.

Energy-Efficient Resource Sharing Scheme With Out-Band D2D Relay-Aided Communications in C-RAN-Based Underlay Cellular Networks

“…According to (18), let K = K 0 k ∪ K m , and sort K in descending order according to D k ,j,x or D k ,j,e m .…”

“…where r k,j,x denotes the out-band channel used by the outband D2D link from the kth cellular UE to the jth out-band D2D relaying UE in subcell x. Actually, (18) means selecting an out-band channel which is the same with the channel of the farthest out-band link and different from the channel of the nearest out-band link.…”

“…Then, out-band D2D communications are receiving more attention since the standardization of in-band D2D communications progresses slowly due to the significant modifications to make in-band D2D UEs appropriately use the cellular spectrum [17]. Finally, there have been lots of research achievements facing the challenges in coordinating the in-band and out-band radio interfaces (e.g., the integrated protocol stacks [18], LTE-w [19]).…”

An efficient SDN‐based LTE‐WiFi spectrum aggregation system for heterogeneous 5G networks

“…This interworking architecture facilitates integrating the LTE spectrum with WiFi spectrum and provides control over both spectra. Furthermore, LWIP is best to provide a better quality of service (QoS) to user and establish seamless mobility between both technologies' interfaces 18 …”

“…The other main part in LWIP architecture is LAL (link aggregation layer) which supports the flow on the basis of radio bearer information.The data packets arrived from core network EPC; no new header would be added to these packets from LAL. The packets from both technologies follow same packet forwarding mechanism and deliver that data packet at IP layer precisely 5,18 …”