8 research outputs found
5G Wireless Network Slicing for eMBB, URLLC, and mMTC: A Communication-Theoretic View
The grand objective of 5G wireless technology is to support three generic
services with vastly heterogeneous requirements: enhanced mobile broadband
(eMBB), massive machine-type communications (mMTC), and ultra-reliable
low-latency communications (URLLC). Service heterogeneity can be accommodated
by network slicing, through which each service is allocated resources to
provide performance guarantees and isolation from the other services. Slicing
of the Radio Access Network (RAN) is typically done by means of orthogonal
resource allocation among the services. This work studies the potential
advantages of allowing for non-orthogonal sharing of RAN resources in uplink
communications from a set of eMBB, mMTC and URLLC devices to a common base
station. The approach is referred to as Heterogeneous Non-Orthogonal Multiple
Access (H-NOMA), in contrast to the conventional NOMA techniques that involve
users with homogeneous requirements and hence can be investigated through a
standard multiple access channel. The study devises a communication-theoretic
model that accounts for the heterogeneous requirements and characteristics of
the three services. The concept of reliability diversity is introduced as a
design principle that leverages the different reliability requirements across
the services in order to ensure performance guarantees with non-orthogonal RAN
slicing. This study reveals that H-NOMA can lead, in some regimes, to
significant gains in terms of performance trade-offs among the three generic
services as compared to orthogonal slicing.Comment: Submitted to IEE
1 Communication Schemes with Constrained Reordering of Resources
Abstract—This paper introduces a communication model inspired by two practical scenarios. The first scenario is related to the concept of protocol coding, where information is encoded in the actions taken by an existing communication protocol. We investigate strategies for protocol coding via combinatorial reordering of the labelled user resources (packets, channels) in an existing, primary system. However, the degrees of freedom of the reordering are constrained by the operation of the primary system. The second scenario is related to communication systems with energy harvesting, where the transmitted signals are constrained by the energy that is available through the harvesting process. We have introduced a communication model that covers both scenarios and elicits their key feature, namely the constraints of the primary system or the harvesting process. We have shown how to compute the capacity of the channels pertaining to the communication model when the resources that can be reordered have binary values. The capacity result is valid under arbitrary error model in which errors in each resource (packet) occur independently. Inspired by the information– theoretic analysis, we have shown how to design practical error– correcting codes suited for the communication model. It turns out that the information–theoretic insights are instrumental for devising superior design of error–control codes. Index Terms—Protocol coding, capacity, secondary channel, energy harvesting
Feedback Halves the Dispersion for Some Two-User Broadcast Channels with Common Message
We investigate the maximum coding rate achievable on a two-user broadcast channel for the case where a common- message is transmitted using fixed-blocklength codes with feed- back. Specifically, we focus on a family of broadcast channels com- posed of two antisymmetric Z-channels. For this setup, we obtain matching upper and lower bounds on the dispersion term in the asymptotic expansion of the maximum coding rate. These bounds reveal that the dispersion is halved compared to the no-feedback case
Wireless access for ultra-reliable low-latency communication: principles and building blocks
Ultra-reliable low latency communication (URLLC) is an important new feature brought by 5G, with a potential to support a vast set of applications that rely on mission-critical links. In this article, we first discuss the principles for supporting URLLC from the perspective of the traditional assumptions and models applied in communication/information theory. We then discuss how these principles are applied in various elements of the system design, such as use of various diversity sources, design of packets and access protocols. The important messages are that there is a need to optimize the transmission of signaling information, as well as a need for a lean use of various sources of diversity