Analytical Modeling of Wi-Fi and LTE-LAA Coexistence: Throughput and Impact of Energy Detection Threshold

Abstract

With both small-cell LTE and Wi-Fi networks available as alternatives for deployment in unlicensed bands (notably 5 GHz), the investigation into their coexistence is a topic of active interest, primarily driven by industry groups. 3GPP has recently standardized LTE Licensed Assisted Access (LTE-LAA) that seeks to make LTE more co-existence friendly with Wi-Fi by incorporating similar sensing and back-off features. Nonetheless, the results presented by industry groups offer little consensus on important issues like respective network parameter settings that promote "fair access" as required by 3GPP. Answers to such key system deployment aspects, in turn, require credible analytical models, on which there has been little progress to date. Accordingly, in one of the first work of its kind, we develop a new framework for estimating the throughput of Wi-Fi and LTE-LAA in coexistence scenarios via suitable modifications to the celebrated Bianchi [1] model. The impact of various network parameters such as energy detection (ED) threshold on Wi-Fi and LTE-LAA coexistence is explored as a byproduct and corroborated via a National Instrument (NI) experimental testbed that validates the results for LTE-LAA access priority class 1 and 3.Index Terms-Wi-Fi, LTE-LAA, 5GHz Unlicensed band Coexistence.

On the Fairness of Wi-Fi and LTE-LAA Coexistence

“…An analytical model for Wi-Fi throughput estimation in a coexistence system was already developed and validated in our prior work [9]. In this work, we extended the prior model to consider different sensing period and use it to investigate 3GPP (and other) notions of fairness.…”

“…IV. THROUGHPUT MODELING OF WI-FI AND LTE-LAA WITH DIFFERENT AIFS We first summarize the analytical modeling of coexistence system proposed in [9] and extend it to include the effect of different sensing regimes prior to backoff (i.e. DIFS for Wi-Fi DCF and T d for LTE-LAA) on throughput.…”

Multi-Cell LTE-U/Wi-Fi Coexistence Evaluation Using a Reinforcement Learning Framework

“…The second algorithm uses a duty cycle approach, similar to the one proposed for LTE-U, but applied to LTE-LAA to improve delay related metrics. Still in the LAA/Wi-Fi coexistence, the authors of [24] provide an analytical study of the influence of energy detection (ED) on the throughput of each technology. Conclusions indicate that maximum system throughput can be achieved by adjusting the ED threshold.…”

On Modeling and Optimizing LTE/Wi-Fi Coexistence with Prioritized Traffic Classes

“…Detailed surveys are given in [14], [15], [16]. On the other side, several works focused on extending Wi-Fioriented Bianchi's approach into modeling LTE/Wi-Fi coexistence [17]- [24]. Vallas et al [17] modeled LTE/Wi-Fi coexistence using Markov chains and investigated maximizing the capacity of LTE in unlicensed bands by specifying the maximum airtime LTE could use.…”

“…Sutton et al [23] focused on analyzing delay of LAA. Mehrnoush et al [24] modeled the impact of energy detection in LTE/Wi-Fi coexistence. Although previous works include interesting analysis and insightful results, they still limited because they focus on a single priority class or fail to include key parameters distinguishing the different LTE and Wi-Fi priority classes, such as the arbitration inter-frame space (AIFS).…”