Project topics and materials
Get Complete Project Material File(s) Now! »
Existing out-band D2D technologies
Face to the great prospect of applications with wireless D2D transmission in personal, public and industrial areas, many competitive out-band D2D technologies have already been developed. A brief comparison of several popular D2D standards are listed in the table below. Bluetooth is probably the most well-known technology which is created by Ericsson in 1994 and was originally developed as RS-232 data cable replacement for short-range communications, such as phones, headsets, keyboards and mice. It was standardized as IEEE 802.15.1, for wireless personal area network (WPAN) with fixed, portable and moving devices within or entering personal operating space. Bluetooth technology now goes way beyond that. High-speed data transfer (up to 24 Mbit/s) is enabled by the use of a Generic Alternate MAC/PHY (AMP) in Bluetooth Core Specification Version 3.0 +HS, where the low power connection models of Bluetooth is still used, while large quantities of data can be transported over the high speed Wi-Fi radio. A new feature of Bluetooth low energy (BLE) protocols is introduced in the most recent Bluetooth v4.0, optimized for devices requiring maximum battery life instead of a high data transfer rate, for example, in favor of WBAN (Wireless Body Area Network), IoT(Internet of Things). BLE consumes between 1/2 and 1/100 the power of classic Bluetooth tech-nology and enables new Bluetooth Smart devices (typically battery-operated sensors) operating for months or even years on tiny coin-cell batteries. Classic Bluetooth, Blue-tooth high speed, and Bluetooth low energy (BLE) protocols altogether brings up prolific applications in different markets including automotive, consumer electronics, health and wellness, mobile telephony, PC and peripherals, sports and fitness, and smart-home. Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has now more than 19,000 companies in the areas of telecommunication, com-puting, networking, and consumer electronics. The installed based Bluetooth-enabled devices alone reached 3.5 billion in 2012 and is forecasted to grow to almost 10 billion by 2018 according to ABI research [ABI, a].
Bluetooth Core Specification provides both link layer and application layer defini-tions, which includes device and service discovery as a fundamental part of the protocol. A Bluetooth device can search for other Bluetooth devices either by scanning the local area for Bluetooth enabled devices or by querying a list of bonded (paired) devices. If a device is discoverable, it will respond to the discovery request by sharing some information, such as the device name, class, and its unique MAC address. Using this information, the device performing discovery can then choose to initiate a connection to the discovered device.
Bluetooth technology operates in the unlicensed ISM band at 2.4 to 2.485 GHz, using a spread spectrum, frequency hopping, full-duplex signal. The applied adaptive frequency hopping (AFH) improves resistance to interference by avoiding using crowded frequencies in the hopping sequence. The range of Bluetooth technology is application specific and may vary according to class of radio used in an implementation (up to 100m).
Bluetooth standard is based upon a master-slave structure. One master may communicate with up to 7 slaves in a piconet (ad-hoc computer network using Bluetooth technology). Each device in a piconet can also simultaneously communicate with up to 7 other devices within that single piconet and each device can also belong to 7 piconets simultaneously. Connection of multiple piconets forms a scatternet in which devices could simultaneously play the master role in one piconet and the slave role in another. Through this topology, a Bluetooth device is capable to connect to many devices.
ZigBee
ZigBee is best suited for periodic or intermittent data or a single signal trans-mission from a sensor or input device, intended for embedded applications requiring low data rate, long battery life and secure networking. Typical applications include: smart lighting, remote control, safety and security, electric meters, medical data col-lection, embedded sensing, etc. It is the leading standard for products in the area of home/building automation, smart energy, health care, etc. ZigBee is based on IEEE 802.15.4 standard, and complete the standard by adding four main components: network layer, application layer, ZigBee device objects (ZDOs) and manufacturer-defined application objects. Its network layer natively supports both star and tree topology, and generic mesh networks. Radios in a mesh network can talk to many other radios (devices) in the network, not just one. The result is that each data packet communicated across a wireless mesh network can have multiple possible paths to its destination. This flexibility provides high reliability and more extensive range. One of the prominent feature of ZigBee is its low-power and its low latency. ZigBee nodes can sleep most of the time, and can go from sleep to active mode in 30ms or less. For this reason, ZigBee is favored in monitor and control sensor systems, especially with battery-operated devices. But the low rate of ZigBee makes it less suitable for social use D2D communication between mobile phones. Bluetooth and wi-Fi direct, for example, can adapt to a much large range of mobile applications.
NFC
NFC is a set of standards for smartphones and similar devices to establish wireless communication with each other by bringing them into close proximity, usually no more than 10 cm. NFC uses magnetic induction between two loop antennas located within each other’s near field, effectively forming an air-core transformer. Typical NFC appli-cations include contactless payment, digital name card exchange, information exchange, access control, fast pairing and connection establishment for other D2D technologies such as Wi-Fi Direct. NFC alone does not ensure secure communications. Higher-layer cryptographic protocols such as SSL can be used to establish a secure channel. However, due to its extreme short range and point to point mode operation, NFC is naturally more secure than other existing D2D technologies. According to ABI research [ABI, b], NFC handsets shipped in 2012 is 102 million, and are anticipated to increase by 481% from 2012 to 2015. Although NFC becomes a popular standard for smartphone D2D connection, due to its extreme short range, similar as ZigBee, it is not suitable for most of the D2D mobile applications.
The coexistence of D2D and cellular transmission in literature studies
The coexistence of D2D and cellular transmission has been mentioned in literature studies for about ten years. D2D in cellular network can exist in two different forms (Figure 2.3). In one form, the pair of D2D users are endpoints (source and sink) of a communication session. In another form, at least one D2D user of the pair act as a relay to form a multi-hop connection between the base station and the endpoint user. Many have proposed to leverage D2D link to increase the system capacity or cellular network coverage, or to balance traffic load between different base stations.
Multi-hop D2D relay
Authors in [Luo et al., 2003], [Bhatia et al., 2006], [Zhao and Todd, 2006], [Papadogiannis et al., 2009], [Law et al., 2010], [Li et al., 2008], [Raghothaman et al., 2011] have proposed multi-hop D2D relay for cellular transmis-sion for the purpose of cellular capacity enhancement. In [Luo et al., 2003], the authors propose hybrid architecture with IEEE 802.11 based secondary network to increase cell’s throughput. The architecture is based on relaying the traffic from base station to mobile nodes with better channel quality. Received relays then use ad-hoc network to deliver information to the destination. The authors propose several ways how to discover and select relay nodes. 3G base station selects relays based on their DL channel quality. The authors also proposed crediting system to motivate users to use their mobile nodes as relays. In [Bhatia et al., 2006], the same authors extend their work to solve the issue of multicast. In pure 3G network, the multicast throughput decreases with increase of multicast group size due to conservative strategy (uses the lowest data rate of all the receivers). By relaying, the throughput of 3G downlink multicast can be significantly increased.
In [Zhao and Todd, 2006], different relay selection criteria are compared: ad-hoc re-laying with low relative interference, with best link and with shortest distance. Selection of relay based on the link quality or interference significantly overcome the selection based on the distance. In [Papadogiannis et al., 2009], the author proposed a dynamic UE relay selection algorithm which reduce signaling and feedback by limiting the number of potential relay candidates for a specific target mobile station. Comparing to the optimal relay selection algorithm, where all the UEs in the cell are considered as candidates for a specific target mobile station, this distance based relay candidates preselecting is proved to significantly reduce the overhead without compromising performance. In [Law et al., 2010], the performance of implementing multi-hop mobile relay in downlink cellular system is analytically computed. The author argues that for the hexagonal cellular network, by careful parametric choices, the capacity due to range extension through multi-hop relaying can exceed that of the corresponding pure cellular network by as much as 70%. The UE relays used are half-duplex and communication link eNB to relay UE and UE-UE link use separate frequency band. In [Li et al., 2008], multihop cellular networks (MCN) are investigated as promising candidate of 4G wireless network for future mobile communications. The authors provide survey of MCN-type architectures and split into three categories: fixed relays, mobile relays and hybrid relays, and comprehensive comparison of those architectures is provided. In the latter part, economics for MCNs are analyzed and the authors claim that mobile relay is more economically feasible in the long term since they could adapt to network growth.
Very recent work covering direct UE-UE communication for relaying has been done by InterDigital,Inc [Raghothaman et al., 2011]. Their initial results shown more than 2 times gain in cell edge throughput and 50% gain in average cell throughput when compared to Reuse 1 macro deployment. It is also shown that by using UE as a relay, significant reduction in the required base station deployment density can be achieved (up to 15 times to maintain 95% coverage with 384 kbps UL service in a Manhat-tan Grid deployment). Moreover, power increased power consumption from relaying is compensated by lower power consumption due to shorter connection duration from higher data rates. In another article [Zhou and Yang, ] , D2D relay is triggered to balance load among neighboring cells. When one cell becomes congested, transmission between an endpoint user and its donor cell can be relayed to a neighboring cell via multihop D2D relay. Multihop route is established based on the number of hops, battery lifetime of the nodes along the route and moving direction of the mobile host. This relaying architecture allows adaptive load balancing and avoids traffic congestion by several congestion states of the base station and reporting the congestion to the mobile nodes.
Interests and challenges of D2D-enabled LTE network
With the popularity of smart devices, and the potential huge market of proximity-based services and applications, there is an urgent need to integrate D2D mode transmissions in the next-generation cellular network to enable efficient discovery and communication between proximate users, and to eventually provide ubiquitous connections and a rich range of services to mobile users. The potential usages that might base on mobile user proximity can be categorized as follows:
• Commercial/social use: local discovery and interaction with connected devices, objects and people; personalized services built around the contextual information obtained
• Enhanced networking: improved connectivity (coverage, speed, cost, etc) to network services by leveraging other local devices a. Commercial/social use: proximity-based services might involve both mobile and fixed devices, for example, smartphones or tablets owned by private users, sensors owned by public sectors, advertising gadgets owned by retail stores, etc. Typical examples of usages include:
• Interactive local guidance: interactive guidance for customers, tourists, com-muters, and users of commercial and public services, using smart beacons, sensors and content servers embedded within objects in the environment. For example, advertisements from nearby stores/restaurants, presentation of art pieces in museums, flight/subway information, vacancy in parking lots, etc. From service receivers’ perspective, a user might preset personalized interests in order to be alerted by services from nearby area, such as notification of a sale, ticketing, restaurant recommendations, traffic jam warning, events or-ganization, etc. A user might also do a real-time search to find momentary interested proximate services.
• Connection to M2M/V2V: D2D-enabled devices can serve as a controller of Machine-to-Machine (M2M) and Vehicle-to-Vehicle (V2V) networks. They can further provide cellular network connection to M2M/V2V, serving as gateways between M2M/V2V and cellular networks.
• Social discovery: discovery of nearby persons linked by social network (e.g. facebook, LinkedIn), with mutual interests (e.g. professional, personal), or at-tending a same event (e.g. party, concert, match), etc.
• Entertainments: usually involves a large variety of personal devices, such as mobile smart devices, game consoles, cameras, TVs, screens, storage memories. Typically for content sharing, local gaming, and local multicasting.
Table of contents :
Acknowledgements
Table of contents
Acronyms
Abstract
Résumé
1 Introduction
2 IntroductiontoD2Dtechnologies
2.1 Overview
2.2 Existing out-band D2D technologies
2.3 The coexistence of D2D and cellular transmission in literature studies .
2.4 LTE D2D
2.4.1 Interests and challenges of D2D-enabled LTE network
2.4.2 D2D in 3GPP LTE standardization
2.5 Conclusion
3 Physical andMAClayer characteristics ofLTED2D
3.1 Overview
3.2 LTE Physical and MAC layer Specifications
3.2.1 Channel Access Method
3.2.2 Frequency and timing synchronization
3.2.3 Transmission procedure basics
3.2.4 Interference coordination
3.3 LTE D2D PHY and MAC layer design choices
3.3.1 General consideration of D2D resource use
3.3.2 Synchronization
3.3.3 D2D discovery
3.3.4 D2D data Communication
3.4 Conclusion
4 Coordinated Scheduling of in-bandD2Ddata communication
4.1 Introduction
4.2 Scheduling issues in coordinated in-band D2D scheduling
4.2.1 Literature studies on in-band D2D resource coordination .
4.2.2 Considerations on scheduling hybrid D2D and cellular transmissions
4.3 Description of studied scenario and objectives
4.4 Proposed scheduling strategy
4.4.1 Mode selection
4.4.2 D2D scheduling
4.4.3 DL scheduling
4.4.4 The originality of proposed scheduling strategy
4.5 Conclusion
5 SystemSimulation
5.1 Overview
5.2 Evaluation Methodology
5.2.1 Introduction to Radio Access Requirements
5.2.2 System simulation principles
5.3 System-level simulation for D2D data Communications
5.3.1 Deployment scenario, network layout, parameters and assumptions
5.3.2 Simulation results
5.3.3 Summary and discussion
6 Conclusion
Résumé de la thèse
Bibliography
