Link adaptation design for ultra-reliable communications

Abstract

Abstract-The fifth generation (5G) of cellular networks is expected to provide connectivity for a wide range of services. This requires the network to encounter novel features. Ultrareliable communications (URC) is one of the considered features, which provides a certain level of communication service almost all the time. This is essential in order to support mission-critical applications, such as industrial automation, public safety, and vehicular communications. This paper studies link adaptation optimization for URC, considering errors in both data and feedback channels. As the implementation of optimal link adaptation is challenging, particularly, for downlink transmissions due to the limited feedback channel, a simple link adaption scheme is also proposed. Results reveal that the performances of the proposed and optimal link adaptation schemes are close. Hence, the proposed scheme can be utilized to efficiently support URC in cellular networks.

A D2D-Based Protocol for Ultra-Reliable Wireless Communications for Industrial Automation

“…As a result, the optimal objective value of problem (22) in the lth iteration is no larger than that achieved by the solution w (I,l−1) n 's and t (I,l−1) n 's, i.e., Monotonic convergence of Algorithm 1 is thus proved. Next, since in Algorithm 1 we use lower-bound to approximate the non-concave functions in problem (15), as shown in (18), (19), and (21), any feasible solution to problem (22) satisfies all the constraints of problem (15).…”

“…First, it can be shown that in the lth iteration of Algorithm 1, the solution obtained in the (l − 1)th iteration is also feasible to problem (22) givenŵ (I) n = w (I,l−1) n (thuŝ a n = a (l−1) n andb n = b (l−1) n ) andt is achievable to problem (22) in the lth iteration. As a result, the optimal objective value of problem (22) in the lth iteration is no larger than that achieved by the solution w (I,l−1) n 's and t (I,l−1) n 's, i.e., Monotonic convergence of Algorithm 1 is thus proved. Next, since in Algorithm 1 we use lower-bound to approximate the non-concave functions in problem (15), as shown in (18), (19), and (21), any feasible solution to problem (22) satisfies all the constraints of problem (15).…”

Reliable Positioning and mmWave Communication via Multi-Point Connectivity

“…However, in the presence of random link blockage and high path-losses, mmWave feedback links are equally unreliable and thus results in redundant retransmission. On the other hand, allowable latency determines a strict upper limit on the number of retransmission attempts [17].…”

MAC layer enhancements for ultra-reliable low-latency communications in cellular networks

“…8·0.143 ms > 1 ms). Since relying on a single (very conservative) transmission would have a significant cost on the spectral efficiency [9], we study the case where the HARQ RTT is reduced to 4 TTIs in order to allow room for one HARQ retransmission. A diagram of the HARQ procedure with reduced RTT is presented in Fig.…”

“…Related to the former, the study in [8] evaluates the downlink latency performance under different TTI durations and load conditions, assuming a mixture of high-priority bursty traffic and best-effort mobile broadband (MBB) traffic. In [9], a link adaptation strategy is presented where the modulation and coding scheme (MCS) is selected according to the target reliability and feedback channel imperfections, assuming that one hybrid automatic repeat request (HARQ) retransmission is allowed.…”