Handover Area Research Articles

Handover mechanisms in VMC systems: Evaluating the reliability of V2X as an alternative to fiber networks in handover areas

Despite advances in communication ways in autonomous driving, including Vehicle-to-Vehicle Communication (V2V), Vehicle-to-Everything Communication (V2X) and Vehicular Micro-clouds (VMC). In this paper, the potential of V2X as a substitution for the artificial connections (mainly optical-fiber cables) between base stations and edge servers are discussed. The quality and latency of communication in Handshake--referring to the scenario of cars moving from one stations operation scope to another ones, is mainly concerned, within the frame of VMC. Additionally, the communication performance, referring to latency performance and data rate performance, for both pure V2X and a combination of LTE and V2X are simulated and analyzed using a Python simulator. Finally, the test results showed that the performance of pure V2X Communication is always superior compared with any combination in every categories as the density of cars gradually increase, which confirms that replace physical inter-station-cables as V2X communication is serious possibility.

NURSES’ COMPLIANCE ON PATIENT HANDOVER PROCESS IN THE PRE-OPERATIVE ROOM OF THE HOSPITAL IN VIETNAM

Background: Ineffective handover is considered a major factor that endangers patient safety in hospitals. Preparing and handing over patients before surgeries directly impact the outcome of the surgery. If errors occur, they could jeopardize the patient’s life.
 Objectives: To determine the level of nurses’ compliance during the pre-operative patient handover process at the anesthesia department. To examine nurses’ evaluation on using a pre-operative patient handover checklist.
 Methods: This was a descriptive observational study with a cross-sectional approach to examine 196 cases of handing over pre-operative patients performed by 53 nurses from the surgical department, maternity department, obstetrics and gynecology department, emergency department, and anesthesia department. Data were collected from November 2019 to February 2020 using “The Checklist of Assessing Nurse’s Compliance on Pre-Operative Patient Handover” and “The Survey Form of Nurse’s Evaluation on Using Pre-Operative Patient Handover Checklist.” Descriptive statistics, including frequencies and percentages, were used for data analysis.
 Results: Nurses’ compliance on handing over pre-operative patients with a high level was 71.9%, and with an average level was 28.1%. The handover areas with low compliance rate included: the patients need to be isolated (63.3%), identifying patient information verbally (75%), identifying patient information by hospital bracelet (77%), time to use antibiotics (78.1%), and marked surgical site (79.6%). Over 90% of nurses agreed on the usefulness of the pre-operative handover checklist.
 Conclusion: The process of handing over pre-operative patients was performed relatively well, but there were still shortcomings to overcome. Nurses positively evaluated the use of the handover checklist for preparing pre-operative patients.

A generator for test instances of scheduling problems concerning cranes in transshipment terminals

We present a test data generator that can be used for simulating processes of cranes handling containers. The concepts originate from container storage areas at seaports, but the generator can also be used for other applications, particularly for train terminals. A key aspect is that one or multiple cranes handle containers, that is, they store containers, receiving the containers in a designated handover area; retrieve containers, handing the containers over in the handover area; or reshuffle containers. We present a generic model and outline what is captured by the test data itself and what is left to be estimated by the user. Furthermore, we detail how data are generated to capture the considerable variety of container characteristics, which can be found in major terminals. Finally, we present examples to illustrate the variety of research projects supported by our test data generator.

A Moving Direction and Historical Information Assisted Fast Handover in LTE-A

Handover is one of the critical features in mobility management of Long Term Evolution Advanced (LTE-A) wireless systems. It allows the User Equipment (UE) to roam between LTE-A wireless networks. LTE-A is purely on hard handover, which may cause loss data if the handover is not fast. In this paper, an advanced technique proposed which combined between the current UE moving direction and its history information. Our proposed tracks the UE positions to discover its direction. When the UE is being near to handover area the UE starts searching in its history to return back the target cell. If the UE trajectory does not exist in its history then the UE and its serving cell start searching for target cell through using cosine function in order to select target cell. Our proposed technique is expected to increase the throughput, reduce the packet delay and loss, and reduce the frequent handovers.

Trajectory estimation based on mobile network operator data for cellular network simulations

In this paper, we present a framework for estimating trajectories of cellular networks users based on mobile network operator data. We use handover and location area update events of both speech and packet data users captured in the core network of the Austrian MNO A1 to estimate the subscribers’ mobility behavior. By utilizing publicly available data, i.e., environmental information, road infrastructure data, transmitter power ranges and antenna characteristics, our approach allows the estimation of subscriber trajectories for both urban and semi-rural environments with a good accordance to the actual trajectories. Additionally, we present a method to estimate a particular subscriber’s movement velocity, on the basis of mentioned data. Furthermore, we propose a methodology to estimate when a particular user started or ended a speech or packet data session during his journey, based on mobility-related network events. With this, our framework enables the creation of reproducible mobility situations for cellular network simulations at system level.

SUPPORTING DISTRESS SIGNALS OVER LOW EARTH ORBIT MOBILE SATELLITE SYSTEMS FOR EMERGENCY INFORMATION ACQUISITION

Low earth orbit (LEO) satellite systems allow a broad range of services to be provided using small, lightweight, cellular-like portable telephones. Exploiting LEO satellites to support distress signals for aircrafts, ships and international travelers is explored in the current paper. A multi-service priority-oriented algorithm is proposed for handling voice, data and emergency signals over LEO satellites. The emergency signal is privileged with service priority so that rescue operation can be carried out as soon as possible. The priority mechanism includes channel reservation as well as joining a queue if no free channel is available as long as the request is roaming in the handover area. In addition, a simplified but efficient approach is suggested for locating the object of an imminent danger situation. As LEO satellites are non-geostationary, the visible period of each spot-beam is small. Consequently, a teletraffic model, that accommodates the mobility of spot-beams as well as the resulting handover rate, is developed in order to gauge the performance of the proposed algorithm. Numerical results for access denying and service-dropping rates are presented for nominal system parameters.

Uplink Capacity Estimation and Enhancement in WCDMA Network

Uplink planification in a WCDMA network consists of estimating the maximum capacity that a cell can support, by using the quality of service equation designed by Eb/N0. We are interested in this work on two different scenarios: an isolated cell and multiple cells. This capacity is adversely affected by interferences due to own mobile stations and to others belonging to neighboring cells. In order to enhance capacity and minimize the blocking probability of new requests in the cell, we have proposed a Freeing Resources algorithm which consists of releasing some mobile stations in the handover area with the overloaded cell. This algorithm is based on freeing 1, 2 and 3 mobile stations of 12.2 kbps and 1 mobile station of 64 kbps.

Performance Evaluation of Handover Channel Exchange Scheme in GSM Network

Properly designed handover procedure in cellular wireless systems are essential for maintaining continuity of a call in progress and minimizing the probability of forced termination, signaling and switching load on the network. In this research, the Handover Channel Exchange (HCE) scheme is modeled and analyzed for channels between two mobiles that are moving in opposite directions across the handover area of adjacent cells of a GSM network. The channel exchange method is interesting since it yields low values of handover failure probability as compared to the case with no channel exchange. This work compares the performance of the cellular system with and without channel exchange, using the data obtained from a GSM network, with MATLAB as the platform for the simulation and analysis. The results as presented show improvement in handover failure probability obtained by using the channel exchange as against that of no channel exchange obtained from the GSM network General Terms: failure Probability, Handover Channel Exchange, call arrival rate.

Partial Bicasting with Buffering for Proxy Mobile IPv6 Handover in Wireless Networks

This paper addresses the Proxy Mobile IPv6 (PMIP) handover using bicasting in mobile/wireless networks. The bicasting scheme can be used to support the PMIP handover, which tends to waste the network resources of wireless links and incurs data losses during handover. We propose an enhanced scheme of PMIP handover, called the bicasting with buffering for PMIP (PBB-PMIP). In the PBB-PMIP handover, the bicasting is performed in the partial region between the Local Mobility Anchor (LMA) and the Mobile Access Gateway (MAG), when a mobile node is in the handover area. The data packets are buffered at the new MAG during handover to reduce data losses and are then forwarded to mobile nodes after handover. By ns-2 simulations, the proposed PBB-PMIP scheme is compared with the existing schemes of PMIP and PMIP with bicasting. The proposed scheme can benefit from the reduction of handover delay and packet loss, and the effective use of the network resources of wireless links, as compared to the existing handover schemes.

Location-based assisted handover for the IP Multimedia Subsystem

The IP Multimedia Subsystem (IMS) is one promising candidate for merging currently deployed circuit-switched and packet-switched voice and data networks into a service-based All-IP architecture. One requirement common to all of these Next Generation Network (NGN) architectures is seamless user mobility – a mandatory feature in order to match with the tremendous success of today’s circuit-switched GSM voice networks. In addition most NGN architectures mandate the support for heterogeneous access technologies like WLAN, WiMAX, GPRS/EDGE, UMTS/HSDPA which raises the need for seamless vertical handover between these access technologies. Despite ongoing standardisation and technology developments like Generic Access Network (GAN), Voice Call Continuity (VCC) or Media Independent Handover (MIH, IEEE 802.21) we argue that there is currently no solution to enable seamless and application-transparent vertical handover in the IMS. In this paper, we review vertical handover standards for IMS and propose a novel vertical handover architecture which relies on geographical location and global network information as primary trigger or support for handover initiation. The underlying Session Initiation Protocol (SIP) notification framework – a Terminal-Centric IMS Location Enabler (LE) – is based on the key concept that location information is one specific kind of presence information which is optimally provisioned by mobile devices: the terminal knows best where it is located. The Location Enabler solicits notifications from the mobile device on specific events – e.g., entering or leaving specific geographical areas – thus dramatically reducing the amount of data transferred over the radio interface when compared to tracking or polling. The SIP registration and Re-Invite message flow is used to convey all handover-relevant information between the IMS core network and the mobile terminal. Using accurate access network measurement results the paper presents a performance estimation of the proposed vertical handover architecture with respect to handover duration and required handover area width at different velocities.

Handover Prioritization with Fuzzy Weightage for Power Rate in Mobile Cellular Communication Systems

A new handover prioritization scheme which is based on considering the weighted sum of received radio power and its rate of change is described. The scheme adaptively varies the weightage for rate of change of power depending on the relative value of radio power received by a mobile. The new prioritization algorithm provides an efficient means of allocating new channels to mobiles in the handover area. Performance improvements achievable by the new scheme are shown by computer simulation of two different single-cell models of a mobile microcellular system.

Handover scheme for mobile cellularcommunication systems

A new scheme for minimising handover failure probability in mobile cellular communication systems, by exchanging channels between two mobiles moving in opposite directions across the handover area of adjacent cells, is presented. The performance evaluation of the new scheme is carried out by computer simulation of a two cell model.