Fundamental tradeoffs among reliability, latency and throughput in cellular networks

Abstract

We address the fundamental tradeoffs among latency, reliability and throughput in a cellular network. The most important elements influencing the KPIs in a 4G network are identified, and the interrelationships among them is discussed. We use the effective bandwidth and the effective capacity theory as analytical framework for calculating the maximum achievable rate for a given latency and reliability constraint. The analysis is conducted in a simplified LTE network, providing baseline-yet powerful-insight of the main tradeoffs. Guidelines to extend the theory to more complex systems are also presented, including a semi-analytical approach for cases with intractable channel and traffic models. We also discuss the use of system-level simulations to explore the limits of LTE networks. Based on our findings, we give some recommendations for the imminent 5G technology design phase, in which latency and reliability will be two of the principal KPIs.

A Flexible Frame Structure for 5G Wide Area

“…Especially since there are fundamental trade-offs in wireless systems between offering high spectral efficiency, low latency, and high reliability [11]. As performance of MBB can approach the limit, while there is a cost of reduced spe operating under strict latency and reliability essentially calls for a flexible air interface d optimizing each link according to its serv This suggests having a dynamic frame struct possibility to perform trade-offs between sp latency, and reliability in coherence with link.…”

Automation for On-Road Vehicles: Use Cases and Requirements for Radio Design

“…In case of failed decoding, the transmitter can be asked to retransmit. All these elements introduce variability to the transmission, having an impact on the achievable reliability and latency [1].…”

“…In fact, 802.11p, which is the de-facto standard to support initial V2X safety applications, uses very simple best-effort transmission approaches making it difficult to ensure high reliability especially at high vehicular density and/or high update rates; see [14] - [16], for example. The open literature, however, claims that a communication reliability 1 above 95% is considered good enough to support the majority of safety applications [14], [17].…”

“…As explained in [1], there is a fundamental tradeoff between throughput, latency and reliability; however, the fact that none of the envisioned applications for 5G (V2X field and many others described in [26]) simultaneously demand stringent requirements of these three performance metrics, suggests that it is feasible, although challenging, to design a single wireless system capable of supporting all these services.…”

“…is the case for mobile broadband (MBB) services. Hence, how to best accommodate both MBB and MCC in the same wireless system presents several new challenges, given the fundamental trade-offs of optimizing for spectral efficiency, latency, and reliability [1]. Examples of wireless system standards with ongoing MTC/MCC related research include (among others) IEEE 802.11p [2] and 3GPP LTE [3], as well as studies on a future 5th Generation (5G) radio standard [4].…”