Last mile

About: Last mile is a research topic. Over the lifetime, 1115 publications have been published within this topic receiving 12720 citations.

Optical Communication in Space: Challenges and Mitigation Techniques

Abstract: In recent years, free space optical (FSO) communication has gained significant importance owing to its unique features: large bandwidth, license free spectrum, high data rate, easy and quick deployability, less power, and low mass requirements. FSO communication uses optical carrier in the near infrared band to establish either terrestrial links within the Earth’s atmosphere or inter-satellite/deep space links or ground-to-satellite/satellite-to-ground links. It also finds its applications in remote sensing, radio astronomy, military, disaster recovery, last mile access, backhaul for wireless cellular networks, and many more. However, despite of great potential of FSO communication, its performance is limited by the adverse effects (viz., absorption, scattering, and turbulence) of the atmospheric channel. Out of these three effects, the atmospheric turbulence is a major challenge that may lead to serious degradation in the bit error rate performance of the system and make the communication link infeasible. This paper presents a comprehensive survey on various challenges faced by FSO communication system for ground-to-satellite/satellite-to-ground and inter-satellite links. It also provides details of various performance mitigation techniques in order to have high link availability and reliability. The first part of this paper will focus on various types of impairments that pose a serious challenge to the performance of optical communication system for ground-to-satellite/satellite-to-ground and inter-satellite links. The latter part of this paper will provide the reader with an exhaustive review of various techniques both at physical layer as well as at the other layers (link, network, or transport layer) to combat the adverse effects of the atmosphere. It also uniquely presents a recently developed technique using orbital angular momentum for utilizing the high capacity advantage of optical carrier in case of space-based and near-Earth optical communication links. This survey provides the reader with comprehensive details on the use of space-based optical backhaul links in order to provide high capacity and low cost backhaul solutions.

High-altitude platforms for wireless communications

Abstract: The demand for high-capacity wireless services is bringing increasing challenges, especially for delivery of the “last mile”. Terrestrially, the need for line-of-sight propagation paths represents a constraint unless very large numbers of base-station masts are deployed, while satellite systems have capacity limitations. An emerging solution is offered by high-altitude platforms (HAPs) operating in the stratosphere at altitudes of up to 22 km to provide communication facilities that can exploit the best features of both terrestrial and satellite schemes. This paper outlines the application and features of HAPs, and some specific development programmes. Particular consideration is given to the use of HAPs for delivery of future broadband wireless communications.

Last mile fulfilment and distribution in omni-channel grocery retailing: a strategic planning framework

Abstract: Purpose – For traditional grocery retailers, the growing importance of online sales means creating new logistics models for omni-channel (OC) management Due to these transformational changes, retail research and practice are lacking a comprehensive view on integrated fulfilment and distribution concepts for home and store deliveries as they have evolved recently The purpose of this paper is to develop a planning framework for last mile order fulfilment in OC grocery retailing and to discuss the advantages and disadvantages of different design concepts Design/methodology/approach – The findings were developed and evaluated by means of explorative interviews with grocery retail and logistics experts Additionally, key literature on last mile order fulfilment and retail supply chain management was reviewed to supplement the integrated OC grocery operations planning framework Findings – OC logistics planning can be structured into back-end fulfilment (eg warehouse and in-store picking) and last mile dis