Novel solutions are required to meet the stringent reliability and latency requirements targeted for the Ultra Reliable Low Latency Communication service class, which emerged with the introduction of 5G new radio. This paper analyses reliability-oriented multi-Connectivity-where the same data packet is independently transmitted through multiple links-as such a solution. Multi-connectivity is first presented at a conceptual level. We then propose a novel admission mechanism to control the number of users operating in multi-connectivity mode. Finally, the reliability and latency enhancement with multi-connectivity in heterogeneous network scenario with multi-service traffic is evaluated via system level simulation. Up to 23% latency reduction and 57% reliability improvements over the single connectivity solution are observed. However such gains are sensitive to the configuration criteria, and the average gains are more modest.

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Long term evolution-wireless local area network (LTE-WLAN) aggregation (LWA) has recently emerged as a promising third generation partnership project (3GPP) Release 13 technology to efficiently aggregate LTE and WLAN at the packet data convergence protocol layer, allowing uplink traffic to be carried on LTE and downlink on both LTE and WLAN. This removes all the contention asymmetry problems of WLAN and allows an optimum usage of both licensed and unlicensed band for downlink. In this paper, we present a new feature of LWA, its flow control scheme, which controls how to aggregate downlink traffic in licensed and unlicensed bands. This aggregation technique exploits user equipment-based flow control feedback in the form of LWA status reports, and can be expanded to work with any number of frequency bands and radio technologies. The same concepts apply to 5G networks, although the performance evaluation provided here is in the context of LTE-Advanced Pro. Simulation results in a typical enterprise scenario show that LWA can enhance user performance up to 8 times over LTE-only, and 3.7 times over WLAN only networks, respectively. The impact of the file size and LWA status report frequency on network performance is also investigated. INDEX TERMSCellular networks, long term evolution (LTE), wireless local area network (WLAN), LTE WLAN aggregation (LWA), flow control, aggregation.

Multi-connectivity with packet duplication, where the same data packet is duplicated and transmitted from multiple transmitters, is proposed in 5G New Radio as a reliability enhancement feature. This paper presents an analytical study of the outage probability enhancement with multi-connectivity, and analyses its cost in terms of resource usage. The performance analysis is further compared against conventional single-connectivity transmission. Our analysis shows that, for transmission with a given block error rate target, multi-connectivity results in more than an order of magnitude outage probability improvement over the baseline single-connectivity scheme. However, such gains are achieved at the cost of almost doubling the amount of radio resources used. Multi-connectivity should thus be selectively used such that its benefits can be harnessed for critical users, while the price to pay in terms of resource utilization is simultaneously minimized.

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