Shih Yang Lin

An early collision warning algorithm for vehicles based on V2V communication

The WAVE (IEEE 1609) standard and vehicular technology create a new opportunity for telematics service. Safety is one of the top issues of telematics service. In this paper, we propose a proactive safety method that can alert drivers before the accident occurs using WAVE. An algorithm named Early Collision Warning Algorithm (ECWA) was proposed in this paper. In ECWA, vehicles broadcast Relationship Information (RI) to neighboring vehicles periodically. Each vehicle calculates whether potential collisions may happen or not upon receiving RI messages. After calculation, ECWA sends warning messages to drivers if the collision will occur. ECWA allows drivers to set the warning level and warning distance by themselves. In our simulation, not only vehicless collisions at an intersection were simulated but also the GPS error range was considered in our design. The results show that ECWA has good performance and can always alert drivers suitably if the GPS error range was small. Even though the GPS error range is large, ECWA also can enhance the hit rate of warning messages. Copyright

Future Applications of VANETs

Current transportation systems face great challenges due to the increasing mobility. Traffic accidents, congestion, air pollution, etc., are all calling for new methods to improve the transportation system. With the US legislation in progress over vehicle communications and EU’s finalization of the basic set of standards over cooperative intelligent transportation systems (C-ITS), vehicular ad hoc network (VANET) based applications are expected to address those challenges and provide solutions for a safer, more efficient and sustainable future intelligent transportation systems (ITS). In this chapter, transportation challenges are firstly summarized in respect of safety, efficiency, environmental threat, etc. A brief introduction of the VANET is discussed along with state of the art of VANET-based applications. Based on the current progress and the development trend of VANET, a number of new features of future VANET are identified, together with a set of potential future ITS applications. The on-going research and field operational test projects, which are the major enabling efforts for the future VANET-based C-ITS, are presented. The chapter is of great interest to readers working within ITS for current development status and future trend within the C-ITS area. It is also of interest to general public for an overview of the VANET enabled future transportation system.

A Signal-Aware Fingerprinting-Based Positioning Technique in Cellular Networks

With the growing number of smart phones, the positioning issue for location-based service (LBS) in cellular networks has got much more popular and important in recent years. This paper proposes a signal-aware fingerprinting-based positioning technique (SAFPPT) in cellular networks, which contains two positioning methods: (i) Continuously Measured Positioning Method (CMPM) and (ii) Stop-and-Measured Positioning Method (SMPM). To verify SAFPPT, we have the case study of implementing the aforementioned two positioning methods in the Android platform for the GSM networks and analyze accuracy using some experiments. Our experimental results show that: (i) the positioning accuracy of CMPM and SMPM are much higher than Google¡¦s ¡§My Location¡¨, (ii) some parameters may affect the positioning accuracy of CMPM, e.g., the moving speed of a user and the number of sampling of the fingerprinting database, and (iii) the staying time of a user may affect the positioning accuracy of SMPM.

The personalized context-aware mobile advertisement system using a novel approaching detection method over cellular networks

With the rapid development of smartphones and personal tablet computers, it brings a greatly growing rate of ubiquitous applications for location‐based services (LBS). One famous LBS is the mobile advertisement. A mobile advertisement system brings benefits and opportunities among users, service providers, and advertisers. In this paper, we propose a personalized context‐aware mobile advertisement system (PCA‐MAS) over cellular networks, which contains two new techniques called (i) approaching detection method (ADM) and (ii) context‐aware ad targeting method (CAADTM). ADM can find some point of interests that a user is approaching; CAADTM pushes advertisements that satisfy users requirement based on the users context, that is, users profile, current time, current position, and so on. Our experimental results show that (i) ADM has the good hit rate to determine those point of interests that a user is approaching within the 150‐m radius of the approaching range, and (ii) CAADTM has the good hit rate of finding appropriate advertisements that a user prefers through the favorite content table filtering, the annoying content table filtering, and the advertisement clicking feedback. Copyright

A farthest-first forwarding algorithm in VANETs

In order to reduce the transmission delay between the source vehicle and the destination vehicle, a Farthest-First forwarding algorithm (FF) algorithm is proposed in this paper to find dissemination paths with fewer hop counts, lower transmission delay, and fewer control packets. The proposed FF algorithm utilizes the general idea of the contention-based technique to choose the farthest vehicle from a sender to be a packet forwarder, which is decided by receivers themselves. In the FF algorithm, each receiver waits for a specific time period when a packet is received. The time period is calculated based on the distance between the sender vehicle and each receiver vehicle, and the waiting time period of the farthest vehicle is always less than other nearby vehicles. When the timer expires, farthest vehicle will first forwards the packet. Although the concept of FF algorithm similar to the greedy forwarding algorithm, the message exchanging for neighboring information maintenance in the proposed FF is unnecessary. Compare to the other mechanisms, the simulation results show that of using the proposed FF algorithm can reduce the transmission delay and fewer hop counts, significantly.

The Cellular Network's Signal-Aware Fingerprint-Based Positioning Technique (SAFPPT)

The Fingerprint-based positioning technique provides an alternative choice for positioning. In order to meet different requirements for traveling, e.g., positioning within a specific area or detection some approaching Point Of Interests (POIs), a Signal-Aware Fingerprint-based Positioning Technique (SAFPPT) is proposed in this paper. SAFPPT contains four positioning methods based on the signal/information of cellular network’s base stations: (i) Positioning Method of Line (PMoL), (ii) Positioning Method of Plane (PMoP), (iii) Approaching Detection Method of Point (ADMoP), and (iv) Approaching Detection Method of Line (ADMoL). The basic idea is that SAFPPT uses user’s cellular information to find the best match records in the pre-established Fingerprint database. SAFPPT can be used in different scenarios of the interested area: (i) Point of Interest (point), (ii) road (line), and (iii) region (plane). The experimental results show that (i) the positioning accuracy of PMoL and PMoP are higher than Google’s “My Location”, (ii) some parameters may affect the positioning accuracy of PMoL, e.g., the moving speed of a user and the number of samples of the Fingerprint database, (iii) the stayed time length of a user may affect the positioning accuracy of PMoP, (iv) ADMoP and ADMoL have higher hit rates to determine the corresponding POIs that a user is approaching within the 150-m radius of the approaching range.

Analysis of the scope of cooperative bandwidth sharing among mobile routers in vehicular networks

This paper investigates the optimal cooperation scope (OCS) for cooperative bandwidth sharing (CBS) in vehicular networks. An analytical model, which comprises the network model, relay schemes, cost model, and vehicular flow model, is presented. Three relay schemes based on optimal single path relay and opportunistic relay for multi-hop CBS are proposed and studied. The OCS is solved as the maximum physical distance or hops between the bandwidth requester and bandwidth helper in the optimal solution to maximize the CBS benefit. OCSs for different environments and with different relay schemes are given in the paper. The results indicate that the OCS is sensitive to the cost weight and may also be larger when using a proper opportunistic relay-based scheme than when using the optimal single path-based one. The results also show that the vehicular density does not affect the optimal cooperation scope much but can result in different CBS benefit. The model and findings of the relations between OCS and the running environment revealed in this paper can be used as a reference for parameter choosing when designing the CBS system in vehicular networks.

Activity recognition for triggering cooperative networking among on-vehicle smart devices

Wireless communication provides convenience service for mobile devices. Considering different wireless characteristics, e.g., WIFI and 3G/4G, a mobile device user may manually change its wireless connection. For intelligent devices, users hope to keep the cooperative networking to work in background automatically. The paper introduces a new method of triggering cooperative networking among portable devices, which is named Active Cooperative Networking Recognition Method (ACNRM). Considering the increasing sensing ability of current smart devices, the method exploits accelerometers in smart devices to recognize some featured activities of the device users, and then trigger different networking operations. The method assists mobile devices to be aware of the changes in their environments without sending periodical message beacons. Thus it can be used for temporary networking among smart devices on vehicles and can save the networking cost.

Analysis of the Optimal Cooperation Scope of Bandwidth Sharing in vehicular networks

This paper investigates the Optimal Cooperation Scope (OCS) for Cooperative Bandwidth Sharing (CBS) in vehicular networks. Three relay schemes based on optimal single path relay and opportunistic relay for multihop CBS are proposed and studied. The OCS is solved as the maximum physical distance or hops between the bandwidth requester and bandwidth helper in the optimal solution to maximize the CBS benefit. OCSs for different environments and with different relay schemes are given in the paper. The results indicate that the OCS is sensitive to the cost weight and may also be larger when using a proper opportunistic relay based scheme than using the optimal single path based one.

A channel busy rate-aware congestion avoidance mechanism for the wireless ad hoc network: channel busy rate-aware congestion avoidance mechanism

This paper presents a Channel Busy Rate-Aware congestion avoidance (CBRA) mechanism for wireless ad hoc network. In the proposed CBRA mechanism, busy rate and utility rate of each nodes wireless channel in a wireless ad hoc connection are used for helping the sender to adjust its transmission rate for congestion avoidance. According to the simulation results that compared CBRA and TCP Reno, the proposed CBRA mechanism can improve performance and fairness in wireless ad hoc network.