Enhanced Soft-Handoff Scheme for Real-Time Streaming Services in Intelligent Transportation Systems Based on CDMA

Great progress of technologies makes intelligent transportation system (ITS) services increasingly desirable. It becomes essential to seamlessly connecting to the Internet for accessing high quality Internet-enabled ITS services. In this context, gateway is recognized as the logical portal to the Internet. The efficiency of gateway regulation hence significantly sways the quality of ITS services. To seamlessly access the Internet in ITSs, a cloud-supported gateway model is proposed in this paper. Accordingly, the weighty load of gateway government, including gateway registration, discovery, selection, dispatching, and handoff, is offloaded from the clients to the appointed cloud servers. Numerical analyses and simulation results suggest that the gateway model proposed in this paper effectively improves the system performance in terms of the packet delivery rate, end-to-end delay, signaling overhead, and gateway connectivity; and, correspondingly enhances the usage experience of Internet-enabled ITS services.

The development of a mobile network to provide intelligent transport system (ITS) services is underway as a national project in Japan called the Smart Gateway, responding to nationwide needs for such a network. System issues for implementation include the necessity of measures for phased system expansion and efficient system maintenance. In addition, a data transmission method must be established to provide uninterrupted communication across microcells following radio signal environment changes to deliver information to fast-moving vehicles. To cope with these issues, this system uses an autonomous decentralized system architecture and supports online extendibility, online maintainability and fault tolerance that are critical to set up a system that operates non-stop. Thus, the authors developed microcell mobility management to enable uninterrupted communication across microcells. The authors developed a prototype incorporating the above methods and made an evaluation.

Recent years have seen a more intensified deployment of Intelligent Transport Systems (ITS) in Polish cities. Work is also underway on the implementation of ITS on the national roads within the National Traffic Management System (KSZR). The research project RID-4D (part of Road Innovations), is designed to fill the gap, which is the lack of systematics of ITS services in Poland. The paper presents a proposal of ITS services systematics, which was developed based on an analysis of key international standards. FRAME architecture and American standards were the basis for the preparation of a standard scheme of ITS services. The results of the work on the KSZR architecture as well as local and regional architectures of urban systems were also taken into account.

A unique feature of code division multiple access (CDMA) systems is the use of soft handoff between cells. Soft handoff, in general, increases the system capacity because while the link between a mobile and one base station is poor, it might be better between the same mobile and some other base station. Hence, the user may transmit at a lower power in a soft handoff situation. Teletraffic analysis of soft handoff is complex because one cannot separate transmission issues from traffic issues. Many papers in the literature have independently analyzed the effect of soft capacity and soft handoff on network performance. Some papers have analyzed the effect of soft handoff on soft capacity but there has been no proper teletraffic analysis that includes both soft capacity and soft handoff. This paper proposes a traffic model for a DS-CDMA cellular network that includes both soft capacity and soft handoff. Network performance is then computed in terms of call blocking.

CDMA (code division multiple access) is a promising air interface technique for digital cellular systems. The soft handoff between base stations is one of many important features of CDMA for the mobile station crossing the cell boundaries. When a mobile station during a call moves to an adjacent MSC (mobile switching center) service area, we propose that the traffic data from the new base station be carried to the old MSC through the link between MSCs. The old MSC receives multiple traffic data from the base stations that are serving the mobile station requesting the inter-MSC soft handoff. We develop an analytical approach for calculating the traffic load on the link by the soft handoffs between MSCs. The service area of an MSC is defined as the union of the service areas of the base stations and is assumed to have a hexagonal shape. The blocking probability of the soft handoff between MSCs due to the shortage of the link capacity is derived by the Erlang loss formula.

Code-division multiple-access (CDMA) cellular systems use soft handoff. Although the capacity of CDMA systems is interference-limited in nature, channel shortages may occur because soft handoff uses several channels simultaneously. To cope with this problem, we propose an improved handoff method that borrows channels from stationary calls participating in soft handoff and allocates the borrowed channels to handoff requests by moving calls when a channel shortage occurs. Borrowing from stationary calls is possible because these calls do not undergo fast-fading and do not require receiver diversity. The proposed method is designed to avoid increased interference resulting from channel borrowing. The proposed channel-burrowing handoff scheme is analyzed in a situation involving both moving and stationary calls. A comparison is made between the performances of the typical IS-95-based handoff scheme and the proposed scheme. Numerical results show that the proposed scheme is better than the IS-95 scheme in view of the handoff refused probability, the handoff queuing delay, and total interference.

As the automotive and telecommunication industries advance, more vehicles are becoming connected, leading to the realization of intelligent transportation systems (ITS). Vehicular ad-hoc network (VANET) supports various ITS services, including safety, convenience, and infotainment services for drivers and passengers. Generally, such services are realized through data sharing among vehicles and nearby infrastructures or vehicles over multi-hop data routing mechanisms. Vehicular data routing faces many challenges caused by vehicle dynamicity, intermittent connectivity, and diverse application requirements. Consequently, the software-defined networking (SDN) paradigm offers unique features such as programmability and flexibility to enhance vehicular network performance and management and meet the quality of services (QoS) requirements of various VANET services. Recently, VANET routing protocols have been improved using the multilevel knowledge and an up-to-date global view of traffic conditions offered by SDN technology. The primary objective of this study is to furnish comprehensive information regarding the current SDN-based VANET routing protocols, encompassing intricate details of their underlying mechanisms, forwarding algorithms, and architectural considerations. Each protocol will be thoroughly examined individually, elucidating its strengths, weaknesses, and proposed enhancements. Also, the software-defined vehicular network (SDVN) architectures are presented according to their operation modes and controlling degree. Then, the potential of SDN-based VANET is explored from the aspect of routing and the design requirements of routing protocols in SDVNs. SDVN routing algorithms are uniquely classified according to various criteria. In addition, a complete comparative analysis will be achieved to analyze the protocols regarding performance, optimization, and simulation results. Finally, the challenges and upcoming research directions for developing such protocols are widely stated here. By presenting such insights, this paper provides a comprehensive overview and inspires researchers to enhance existing protocols and explore novel solutions, thereby paving the way for innovation in this field.

Code division multiple access (CDMA) is a promising candidate for radio transmission technologies in future mobile communication systems, such as International Mobile Telecommunications (IMT)-2000. As a unique feature of CDMA systems, soft handoff can increase the system capacity but it may also increase the signaling traffic. This paper investigates the effect of soft handoffs on the signaling traffic in IMT-2000 networks in terms of processing load at each physical entity (PE) and signaling load at each signaling link. Compared with hard handoffs, soft handoffs require more processing, especially at the access network and slightly increase signaling load.

Performance Analysis of Trunk Network for Inter-MSC Soft Handoffs in CDMA Cellular Communication Systems

Existing soft handoff techniques lead to plenty of out-of- sequence packets during downward vertical handoffs (DVHOs). In this paper, we present two new network-layer soft vertical handoff schemes, called SHORDER and E-SHORDER. The former can prevent mobile nodes from receiving reordered packets during DVHOs with a low overhead. The latter further hinders their correspondent nodes from receiving out-of-order packets caused by mobile nodes' DVHOs. Then, we analyze the performance of our proposed approaches. By experiments, we show that they have a good effect in practice.

Intelligent transport systems (ITSs) play a key role in people's daily activities. ITSs significantly improve mobility offering a variety of services to a vast number of users that increase on a daily basis, as more and new services are introduced. These services are based on advanced information and communication technologies (ICTs) and rely strongly on connectivity and computing resources. However, technical vulnerabilities of the technologies used in ITS, as well as the increase in users' awareness has brought security and privacy concerns to the forefront. This article aims at identifying a set of privacy concepts that provide the bases for designing trustworthy ITS services identifying possible threats and users' privacy concerns. A key contribution of the article is a roadmap that presents in detail how for every ITS function corresponding to privacy concepts can be realized for overcoming specific threats and users' privacy concerns in a smart city context.

The application of intelligent transportation systems (ITS) solutions for government agencies in the United States raises special concerns about how information collected by new ITS-related systems will be used and maintained. In the United States, Freedom of Information Act laws require almost all government agencies to provide the general public with access to government records, including electronic records. Government agencies are also required by state and federal courts to provide access to their records. Consequently, as government agencies apply ITS solutions, they must examine issues related to data retention and access. The development of data access and retention was examined in the case of the Capital Wireless Integrated Network (CapWIN) project, a partnership of numerous government agencies and universities of the Washington, D.C., metropolitan region that is developing the first interjurisdictional, interagency integrated and scalable wireless transportation fleet and public safety communications network in the United States. Data retention and access issues for the CapWIN system are explored in a context designed to provide guidance for the future development of ITS services.

To meet the prospective demands of intelligent transportation systems (ITS), the Release 14 (Rel-14) and Rel-15 of the Long Term Evolution (LTE) specifications include solutions for enhanced vehicle-to-everything (V2X) communications. While the technical enablers of Rel-14 are suitable for delivering basic safety messages, Rel-15 supports more demanding ITS services with stringent latency and reliability. Starting in Rel-15 and continuing in Rel-16, the 3GPP was developing a novel radio interface for 5G systems, termed the New Radio (NR), which will enable ultra reliable and low latency communications suitable even for the most demanding ITS applications. In this paper, we overview the new V2X-specific features in Rel-15 and Rel-16. Further, we argue that future V2X and automotive radar systems may reuse common equipment, such as millimeter-wave antenna arrays. We finally discuss the vision of joint vehicular communications and radar sensing as well as characterize unified channel access for millimeter-wave vehicular communications and radar sensing.

Following the newly adopted European Directive on Intelligent Transport Systems (ITS) 2010/40/EU, officially published on November 30th 2023 under the new code (EU) 2023/2661, opportunities arise for the entire industry. The main aim of the Directive is to promote coordinated deployment of intelligent transport systems in accordance with technological development and user needs. It provides a framework for developing and implementing technologies to improve transportation systems' efficiency, safety, and sustainability within the European Union (EU) and member states. The new European legislation should ensure that ITS applications in the field of road transport enable seamless integration with other modes of transport thus facilitating a shift to those modes whenever possible. This will in time improve the safety, efficiency and accessibility of the European transportation system. In this paper, we are analyzing the main objectives of the EU initiative and changes compared to the initial Directive of 2010 with special regard to changes in Priority III, safety and Priority IV, ITS services for connecting, cooperation and automatization of mobility. Although all key changes are analysed the special focus was on critical services such as road safety-related traffic information services, to be made available across Europe.

Intelligent Transport Systems (ITS) have received growing attention recently driven by technical advances in Industrial Internet of Vehicles (IIoV). In IIoV, vehicles report traffic data to management infrastructures to achieve better ITS services. To ensure security and privacy, many anonymous authentication-enabled data reporting protocols are proposed. However, these protocols usually require a large number of preloaded pseudonyms or involve a costly and irrevocable group signature. Thus, they are not ready for realistic deployment due to large storage overhead, expensive computation costs, or absence of malicious users' revocation. To address these issues, we present a novel data reporting protocol for edge-assisted ITS in this paper, where the traffic data is sent to distributed edge nodes for local processing. Specifically, we propose a new anonymous authentication scheme fine-tuned to fulfill the needs of vehicular data reporting, which allows authenticated vehicles to report unlimited unlinkable messages to edge nodes without huge pseudonyms download and storage costs. Moreover, we designed an efficient certificate update scheme based on a bivariate polynomial function. In this way, malicious vehicles can be revoked with time complexity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathcal {O}$</tex-math></inline-formula> (1). The security analysis demonstrates that our protocol satisfies source authentication, anonymity, unlinkability, traceability, revocability, nonframeability, and nonrepudiation. Further, extensive simulation results show that the performance of our protocol is greatly improved since the signature size is reduced by at least 8%, the computation costs in message signing and verification are reduced by at least 56% and 67%, respectively, and the packet loss rate is reduced by at least 14%.