Handover

Seamless handover in wireless networks is to guarantee both service continuity and service quality. In WiMAX, providing scalability and quality of service for multimedia services during handover is a main challenge because of high latency and packet loss. In this paper, we created four scenarios using Qualnet 5.2 Network Simulator to analyze the hard handover functionality of WiMAX under different conditions. The scenarios such as Flag with 5 and 10 sec UCD and DCD interval values, Random mobility scenario and DEM scenario using 6 WiMAX Cells have been considered. This study is performed over the real urban area of JNU where we have used JNU map for scenarios 1, 2 and 3 but for scenario 4, the JNU terrain data has been used. Further, each BS of 6 WiMAX cell is connected to four nodes. All nodes of each scenario are fixed except Node 1. Node 1 is moving and performing the handover between the different BSs while sending and receiving real time traffics. Flag mobility model is used in Scenario 1, 2 and 4 to model the movement of the Node 1 while we use random mobility model in sceanrio3. 5 seconds time interval is used for Scenarios 1, 3, and 4 while 10 seconds time interval is used for scenario 2 to study the effect of management messages load on handover. Further, the statistical measures of handover performance of WiMAX in terms of number of handover performed, throughput, end-to-end delay, jitter, and packets dropped are observed and evaluated.

This paper provides an overview of cellular networks and wireless Internet. It focuses on the problems of providing multimedia services over these networks, and highlights the latest developments in the area. This is done by providing brief descriptions, and providing a wealth of pointers to where the relevant information can be obtained. The paper consists of four main sections corresponding to protocol layering: wireless data link layer for cellular systems and the supporting of multimedia in these environments; wireless network layer, namely Mobile IP needed to support mobility in a wireless Internet; wireless transport layer, namely the extensions to Internet's TCP; wireless application layer. Regarding cellular systems, we present an overview of multiple access techniques, transmission aspects, and quality of service issues in the data link layer of these systems. The section on wireless network layer provides a brief introduction to the Internet technologies, then it illustrates the deficiencies of the current Internet Protocol (IP) for supporting wireless/mobile applications and shows how the new Mobile IP protocol overcomes these deficiencies, and how mobility is handled in these wireless Internets. The next section tackles the problem of reliable communication in wireless Internet, and the related problems of TCP over Mobile IP. The final section focuses on application layer issues in wireless data, namely handover and developing Web applications for mobile computers.

Joseph Yu-shek Cheng and Emile Kok-Kheng Yeoh (focus issue editors) (2016), Contemporary Chinese Political Economy and Strategic Relations: An International Journal (CCPS), Vol. 2, No. 2, August/September 2016 (Focus – From Handover to Occupy Campaign: Democracy, Identity and the Umbrella Movement of Hong Kong), pp. 635-984 (350 pp. + xviii). [Scopus] <http://rpb115.nsysu.edu.tw/p/404-1131-154708.php?Lang=en> <http://icaps.nsysu.edu.tw/var/file/131/1131/img/2375/165090456.pdf> <https://www.dropbox.com/s/laezk1sfx85mr93/CCPS-V2N2-full-issue.pdf>

The applicability of the United Nations Convention on Contracts for the International Sale of Goods of 11 April 1980 (CISG), the most important international convention unifying matters of international contract law, to an international sales contract according to Article 1(1)(a) CISG depends on both parties having their place of business in different Contracting States. The People's Republic of China was among the first States to ratify the CISG, meaning that all companies residing in the PRC do have - at least at first sight - their place of business in a Contracting State of the CISG. This result, however, causes difficulties when companies from Hong Kong and Macao are concerned, as these two territories were originally colonies of two States that did ratify the CISG (i.e. the United Kingdom and Portugal), and when returning to the PRC in 1997 resp. 1999, Hong Kong and Macao were given the status of Special Administrative Regions with a high degree of autonomy also in legal matters. Against this background, the present paper discusses the question of Hong Kong and Macao are to be treated as parts of a Contracting State under the CISG. It argues that the answer must be in the affirmative as Article 97 CISG expressly provides that a Contracting State comprising different territorial units has to make an express declaration if it selects not to apply the CISG to certain of its territorial units, and the PRC has not done so.

The challenge of elimination of redundant handovers is getting more significant while femtocells with small radius are deployed in networks. The utilization of the femtocells results to more frequent initiation of a handover procedure. This paper focuses on an adaptation of actual level of hysteresis margin according to the position of the user in a cell. The hysteresis margin is commonly used parameter for elimination of redundant handovers. The purpose of this paper is to propose mechanism with minimum requirements on conventional network and user's equipment and with a simple implementation. Evaluations of proposal in term of efficiency of the redundant handovers reduction as well as an impact on the user's throughput in 4G wireless networks are carried out. The results show significant reduction of the amount of handovers while reducing the impact on the throughput.

The aim of equipping a wireless network with a mobile relay node is to support broadband wireless communications for vehicular users and their devices. The high mobility of vehicular users, possibly at a very high velocity in the area in which two cells overlap, could cause the network to suffer from a reduced handover success rate and, hence, increased radio link failure. The combined impact of these problems is service interruptions to vehicular users. Thus, the handover schemes are crucial in solving these problems. In this work, we first present the adaptive handover hysteresis scheme for the wireless network with mobile relay nodes in the high-speed train scenario. Specifically, our proposed adaptive hysteresis scheme is based on the velocity of the train. Second, the handover call dropping probability is reduced by introducing a modified call admission control scheme to support radio resource reservation for handover calls that prioritizes handover calls of mobile relay over the other calls. The proposed solution in which adaptive parameter is combined with call admission control is evaluated by system level simulation. Our simulation results illustrate an increased handover success rate and reduced radio link failures.

Problems: It is important that nurses are aware of the importance of correct
communication, so it is fundamental to understand the implications that poor
communication can bring to their care delivery.
Rationale: Thus, this study becomes pertinent due the need to invest in the search for
current scientific evidence, for such an important and characteristic moment of nursing,
the shift change.
Objectives: This document intends to identify the benefits of a correct transmission of
information in the handover, for the nurse and, fundamentally for the patient.
Methodology: It was carried out an Integrative Literature Review (RIL), a research was
done on the online platforms B-on, Medline and RCAAP. When analyzing the literature,
we intend to answer the research question: What information should the nurse transmit
during the handover, taking into account the patient's self-care deficit in the different
human needs? "
In order to select the relevant articles, we used inclusion and exclusion criteria, and a total
of 5 scientific articles were obtained, which were later submitted to an analysis using the
P [I] [C] OD method.
Results: After analyzing the articles, the literature shows that the moment of the shift is
sometimes undervalued by nurses, and it has been verified that there is a wide range of
literature that advocates the importance of an assertive and effective communication for
reduction of error in clinical context. It has been observed that there are many barriers to
a correct transmission of information in the handover, as well as, which strategies the
nurses put in order for this moment to occur correctly, in order to minimize the error.
Having these skills can lead to less fatigue, increased productivity, effective time
management and improved quality in caring.
Conclusions: the shift is undoubtedly a fundamental moment for a guarantee of continuity
of care. Therefore, it becomes fundamental that an assertive and standardized
communication occurs, minimizing possible failures in the transmission of information,
so that the information the incoming nurse, can continue the care that the patient needs.
In this way it can lead to an increase of productivity, effective management of the time
and the improvement in quality of the care. It is necessary to realize that not all the
information produced by the nurses in the shift is relevant to the care guarantee, so it is
up to each nurse to define and find strategies so that at the moment of handover, the nurse
receiving the shift, can conceive, immediately, a care plan, as well as set priorities in
nursing care. The SBAR model is a protocol that has been introduced to manage the
information to be transmitted in handover and that have obtained excellent results, so it
was concluded that this methodology of transmission was the one that best suits the
theoretical assumptions of the continuity of nursing care.
Keywords: handover, shift change, health communication, continuity of care, patient
safety.

It is a handbook of UMTS/LTE/EPC CSFB call flows.

This document is originally edited by Justin MA and it is free to share to everyone who are interested.

All reference/resource are from internet. If there is any copy-right issue, please kindly inform Justin by [email protected].

Thanks for your reading!

The Fifth Generation (5G) networks, including the 5G Vehicular Cloud Computing (5G-VCC) systems, have evolved rapidly offering multiple services to users. The operating principles of vehicular networks, Cloud Computing (CC), Fog Computing (FC), Mobile Edge Computing (MEC) and Software Defined Networks (SDN) are applied to 5G infrastructures. In a 5G-VCC system, the vehicles are equipped with On-Board Units (OBUs) which communicate with each other as well as with Road Side Units (RSUs). Each RSU interacts with a Cloud infrastructure which offers vehicular services with strict Quality of Service (QoS) requirements, including Driver Assistance (DA), Passengers Entertainment and Information (PEnI) and Medical (MED) services. Dense deployments of 5G access networks are also implemented, called Ultra Dense Networks (UDNs), aiming to support high data rates produced by an increased number of vehicular users. In this environment, heterogeneous technologies are used to transfer the network services to vehicles. Optimal manipulation of the communication resources is required, while at the same time vehicular users should always obtain connectivity to the most appropriate network access technology, in order the constraints of the vehicular services to be satisfied. In this thesis, existing schemes for resource allocation as well as for mobility management are studied, while novel solutions are proposed for each topic.

Initially, the theoretical background of the 5G wireless networks and 5G-VCC systems is described. Subsequently, the available delivery models for providing cloud services in 5G infrastructures are mentioned, while the available 5G-VCC architectures and the communication models are presented.

Regarding the topic of the manipulation of the available network resources in 5G-VCC systems, the available Medium Access Control schemes (MAC schemes) are studied, while at the same time resource scheduling algorithms implemented at the MAC layer of 5G-VCC systems are described. Subsequently, two novel solutions are proposed to optimize the resource allocation process in modern networks. The first one is called FLS Advanced (FLSA) and optimizes the resource allocation for real-time services. Additionally, the second one is called FLS Advanced - Cross Carrier (FLSA-CC) and is specialized for LTE-Advanced (LTE-A) access networks where carrier aggregation is applied in order to provide widened bandwidth to the users. The evaluation of the proposed algorithms is performed through extended experiments. Simulation results show that the proposed algorithms outperform existing solutions.

The mobility management requirements arising at the 5G-VCC systems are also studied. As a result of this study, initially three methods for calculating the significance of the criteria affecting the mobility management are proposed, namely the Trapezoidal Fuzzy Analytical Network Process (TF-ANP), the Trapezoidal Fuzzy Adaptive Analytical Network Process (TF-AANP) and the Pentagonal Fuzzy Analytical Network Process (PF-ANP). Subsequently, three network selection algorithms are proposed, namely the Trapezoidal Fuzzy TOPSIS (TFT), the Trapezoidal Fuzzy TOPSIS with Adaptive Criteria Weights (TFT-ACW) and the Pentagonal Fuzzy TOPSIS (PFT). Following this study and regarding the research results of the implemented algorithms, a mobility management scheme is proposed. This scheme takes into consideration the Signal to Noise plus Interference (SINR) parameters as well as the velocity of the vehicular users to evaluate the necessity of performing a handover. Then, it applies the PFT algorithm to select the most appropriate network for the user. Experimental results showed that the proposed scheme outperforms the existing solutions described in the research literature.

In the modern era of technology, the high speed internet is the most important part of human life. The current available network is reckoned to be slow in speed and not be up to snuff for data transmission regarding business applications. The objective of handover mechanism is to reassign the current session handle by internet gadget. The globe needs the next generation high mobility and throughput performance based internet model. This research paper explains the proposed method of design and development for handover based 5G cellular network. In comparison to the traditional method, we propose to control the handovers between base-stations using a concentric method. The channel simulator is applied over the range of the frequencies from 500 MHz to 150 GHz and radio frequency for the 700 MHz bandwidth. The performance of the simulation system is calculated on the basis of handover preparation and completion time regarding base station as well as number of users. From this experiment we achieve the 7.08 ms handover preparation time and 9.98 ms handover completion time. The author recommended the minimum handover completion time, perform the high speed for 5G cellular networks.

Fifth generation (5G) Vehicular Cloud Computing (VCC) systems use heterogeneous network access technologies to fulfill the requirements of modern services. Multiple services with different Quality of Service (QoS) constraints could be available in each vehicle, while at the same time, user requirements and provider policies must be addressed. Therefore, the design of efficient Vertical Handover (VHO) management schemes for 5G-VCC infrastructures is needed. In this paper, a novel VHO management scheme for 5G-VCC systems is proposed. Whenever the user satisfaction grade becomes less than a predefined threshold, VHO is initiated and network selection is performed, considering the velocity of the vehicle, network characteristic criteria such as throughput, delay, jitter and packet loss, as well as provider policy criteria such as service reliability, security and price. The proposed scheme uses linguistic values for VHO criteria attributes represented by Interval Valued Pentagonal Fuzzy Numbers (IVPFNs) to express the information using membership intervals. The VHO scheme is applied to a 5G-VCC system which includes 3GPP Long Term Evolution (LTE) and IEEE 802.16 Worldwide Interoperability for Microwave Access (WiMAX) Macrocells and Femtocells, as well as IEEE 802.11p Wireless Access for Vehicular Environment (WAVE) Road Side Units (RSUs). Performance evaluation shows that the suggested method ensures the Always Best Connection (ABC) principle, while at the same time outperforms existing VHO management schemes.

ABSTRACT The introduction of Long Term Evolution (LTE) and the Evolved Packet Core (EPC) has led to a proliferation of data hungry mobile devices and services. The result is a surge in mobile data traffic compelling operators to look for solutions to improve system scalability and flexibility to cope with this traffic surge. One such solution is the distribution of the EPCs data plane entities, that is, by moving them closer to the network edge. Within the EPC&amp;#39;s standardized gateway selection framework for IP traffic routing in a distributed environment, mobility of User Equipment (UEs) with IP traffic destined to local networks leads to nonoptimal routing. Furthermore, when a UE has multiple Packet Data Network (PDN) connections which include local and central core network connections, there is a high likelihood of the occurrence of nonoptimal routing for the local connections. Such nonoptimal routing may lead to inefficient use of backhaul network resources and may further result in degradation of Quality of Service for delay sensitive applications. In this paper, we investigate and propose a solution to the nonoptimal routing problem for local IP traffic in such an environment. The testbed implementation and evaluation shows that the proposed scheme can improve the routing and ensure service quality for local IP traffic in a distributed EPC network.

The need for reliable mobility support in low-power wireless networks (LPWNs) is ever increasing in application contexts such as health-care monitoring, industrial automation, smart cities and generally in the “Internet of Things”. The wireless nature, the environmental context and scalability features of these applications usually impose the use of low-power and low-cost devices. Namely, these devices feature simple single radio transceivers, communicating at very low TX/RX power and using basic electronics and antennas. These characteristics lead to unstable, asymmetric and unreliable wireless links, which in turn affect the quality of service of the LPWN. This quality of service is even more difficult to achieve when the applications at stake support nodes mobility, as in heath-care monitoring and preventive/corrective maintenance in industrial environments. In this context, this Thesis aims at guaranteeing reliable and timely communication in LPWN under nodes mobility. The main research objectives of this Thesis are: (i) to devise a reliable and fast hand-off mechanism for LPWNs, using state-of-the-art (SOTA) commercial-off-the-shelf (COTS) technologies, (ii) to integrate the proposed hand-off mechanism within a SOTA/COTS protocol stack and (iii) to support the mobility solution with analytical, simulation and experimental evaluations. Within this research context, we designed a hard hand-off mechanism (dubbed smartHOP) based on averaged single link quality parameters — received signal strength indicator (RSSI) or signal-to-noise ratio (SNR). We fine-tuned the most relevant hand-off parameters — lower threshold level (T` ), hysteresis margin (HM), window size (ws), stability monitoring (m) — with preliminary experiments. We studied the impact of radio channel parameters — path loss exponent and shadowing standard deviation — on handoff performance (packet delivery ratio and hand-off delay) based on a probabilistic model. A simulation model was designed to further study the impact of link monitoring frequency (window size) and the stability monitoring parameters on hand-off performance. An extended experiment with a more realistic environmental set-up was performed to better fine-tune the hand-off parameters. We integrated smart-HOP within the commodity RPL/6LoWPAN routing protocol (dubbed mRPL) in a simple, effective and backward compatible manner. We also developed a soft hand-off mechanism to seamlessly change parent nodes while moving. In order to enable soft hand-off, we activated neighbor overhearing mechanism to eliminate the Discovery Phase in the hand-off process. We applied the soft hand-off model on top of mRPL (mRPL+) to further increase network performance. Overall, results indicate that mRPL and mRPL+ are able to provide network connectivity and responsiveness by switching between parents in a short period of time while successfully delivering most of data packets. mRPL and mRPL+ are able to provide good reliability (≈ 100% packet delivery ratio) compared with RPL (delivering < 50% of data packets). The average hand-off delay in RPL is ≈ 3 s, while it reduces to 85 ms in mRPL and 4 ms in mRPL+.

A novel distributed scheme that combines cooperative ARQ with the spectrum leasing paradigm is proposed and analyzed. The strategy harnesses the opportunistic gains of cooperative communications, while inherently providing a spectrum-rewarding incentive for the otherwise non-cooperative relays to assist the source's transmission. As in cooperative ARQ, the source might decide to hand over the possible retransmission slots to nearby stations that were able to decode the original transmission. In the proposed scheme, however, in exchange for the cooperation, the relaying station is also awarded an opportunity to exploit the retransmission slot for its own traffic. Arbitration of relays' retransmissions is performed via an auction mechanism, with the source, the competing relays and the transmission slot acting as the auctioneer, the bidders and the bidding article, respectively. Auction theory (more generally, the theory of Bayesian games) is applied to analyze the scheme performance. It is noted that the setting here can be alternatively seen as a practical framework for implementation of propertyrights cognitive radio networks. Numerical results and analysis show that the proposed scheme enables an efficient dynamic resource allocation that provides relevant gains (e.g., transmission reliability) for both the original source (primary) and the cooperating nodes (secondary users).

Satellite networks have traditionally been considered for specific purposes or as a backup technology. Recently, new satellite technologies have been pushed to the market enabling high-performance satellite access networks. On the other hand, network architectures are taking advantages from new emerging technologies such as Software-Defined Networking (SDN) and Network Functions Virtualization (NFV).

Wireless Communications have increased rapidly in recent years. Wireless LAN, Code Division Multiple Access (CDMA), Universal Mobile Tele-Communication System (UMTS), GPRS (General Packet Radio Service), Bluetooth, 3G (Third Generation networks), and GPS (Global Positioning System), etc., are common wireless technologies that are commercially available.

Joseph Yu-shek Cheng and Emile Kok-Kheng Yeoh (focus issue editors) (2017), Contemporary Chinese Political Economy and Strategic Relations: An International Journal (CCPS), Vol. 3, No. 2, July/August 2017 (Focus – Hong Kong Twenty Years after the Handover: Quo Vadis?), pp. 523-999 (477 pp. + xv). [Scopus] <http://rpb115.nsysu.edu.tw/p/404-1131-175227.php?Lang=en> <http://rpb115.nsysu.edu.tw/var/file/131/1131/img/2374/CCPS3(2)-full-issue(2).pdf> <https://www.dropbox.com/s/4d4hackrq0dz743/CCPS-V3N2-full-issue.pdf>

Hard handover mechanism is adopted to be used in 3GPP Long Term Evolution (3GPP LTE) in order to reduce the complexity of the LTE network architecture. This mechanism comes with degradation in system throughput as well as a higher system delay. This paper proposes a new handover algorithm known as LTE Hard Handover Algorithm with Average Received Signal Reference Power (RSRP) Constraint (LHHAARC) in order to minimize number of handovers and the system delay as well as maximize the system throughput. An optimized system performance of the LHHAARC is evaluated and compared with three well-known handover algorithms via computer simulation. The simulation results show that the LHHAARC outperforms three well-known handover algorithms by having less number of average handovers per UE per second, shorter total system delay whilst maintaining a higher total system throughput.

The Chinese Communist Party (CCP) engaged actively with Hong Kong and Macau Triads during the 1980s and 1990s, in order to ensure that they would not disrupt the negotiation process and the festivities for the handover of these colonial territories to China. The CCP considered triads as a potential threat, owing to their former links with the Nationalist Party troops and nationalist gangsters. Since then however, to counter the indigenization of the Republic of China on Taiwan and the rise of Taiwanese identity and in order to promote the unity of a “greater China”, the CCP has encouraged the nationalist stance of Hongmen networks, to which the Triads belong, as well as their political  activism. This case highlights the reality of a United Front policy that has been ongoing over the last forty years, towards these social margins, yet in a perspective that has gradually reversed as a consequence of a paradigmatic shift that reflects the CCP’s own political transformation.

Regarding to this study, an extensive review of secure and fast handovers schemes were studied with the aim of solving security problems and authentication server computational overhead experienced in the existing schemes in wireless fidelity based networks. The complete verification scheme outlined in IEEE 802.11i network is unsuitable to be deployed so as to support the user's seamless mobility. The contribution of this paper suggested a robust delivery of handoff keys for internetworking and intranetworking schemes with a dedicated trust relationship model existing in diverse domains. Inter-access point protocol was used to transfer handover credentials in an intra-domain network. Likewise, an inter-access control-tunnelling protocol with opportunity key caching and pairwise master key caching are suggested for inter-domain security context-transfers. Man-in-the-middle attacks are tasked to break mutual authentication for wireless networks. This paper pinpoints out that the suggested fast handover authentication scheme in our study outperforms the scheme of Wang and Prasad and other schemes mentioned in the extant studies. The proposed authentication scheme prevents replay attacks, masquerading and message modification.

Providing diverse broadband services economically every time, even to mobile subscribers will be a major challenge for the telecommunication community. IEEE 802.16 networks are going to provide broadband wireless access as a fixed wireless broadband solution. However, the IEEE 802.16e as an amendment to 802.16d which expands the standard to allow mobile subscriber station. As handover is an important aspect of mobile wireless communications, we have studied and analyzed concepts, functionalities and keys aspects to provide mobility over IEEE802.16e. This paper looks particularly at the advanced features introduced by the IEEE802.16e standard for mobility in WiMax systems in order to prove that the enhanced IEEE 802.16 e system has the capability to fulfill the requirements regarding the mobility management of future telecommunication systems.

One of the key elements in the emerging, packet-based long term evolution (LTE) cellular systems is the deployment of multiple femtocells for the improvement of coverage and data rate. However, arbitrary overlaps in the coverage of these femtocells make the handover operation more complex and challenging. As the existing handover strategy of LTE systems considers only carrier to interference plus noise ratio (CINR), it often suffers from resource constraints in the target femtocell, thereby leading to handover failure. In this paper, we propose a new efficient, multi-objective handover solution for LTE cellular systems. The proposed solution considers multiple parameters like signal strength and available bandwidth in the selection of the optimal target cell. This results in a significant increase in the handover success rate, thereby reducing the blocking of handover and new sessions. The overall handover process is modeled and analyzed by a three-dimensional Markov chain. The analytical results for the major performance metrics closely resemble the simulation results. The simulation results show that the proposed multi-objective handover offers considerable improvement in the session blocking rates, session queuing delay, handover latency, and goodput during handover.

The IP Multimedia Subsystem (IMS) has been selected as a telecommunication industrial standard for the signal processing among heterogeneous access networks, and it is also responsible for mobility management. However, the mobility of the user equipment (UE) may disrupt or even intermittently disconnect an ongoing session, which heavily affects the satisfaction of the users. Therefore, how to reduce the service disruption time is an important issue. This paper proposed a network-based handover scheme, abbreviated as NHO, in IMS-based network. When a UE moves to a new network and completes the attach procedure during a mid-session, the access gateway (e.g. PDN-GW in LTE) will send a SIP PUBLISH message with secure context transfer request to the newly attached P-CSCF. Then the new P-CSCF will accomplish the secure context transfer to get the context information of the UE, and then perform the IMS registration procedure and the IMS session setup procedure on behalf of the UE in parallel. The novelty of NHO is that it only requires minor modifications to the attach procedure, and enhances MME, Serving-GW, PDN-GW, HSS, and P-CSCF slightly. Analytical results based on queuing theory show that NHO can shorten the handover delay as compared with current alternatives.

A heterogeneous network (HetNet), typically a combination of macrocells and small cells, is a popular solution for Long Term Evolution (LTE) based 4G or 5G technologies as it can provide ubiquitous and cost-effective broadband user experience with higher network capacity. However, the interference issues are more complicated in LTE HetNets. The mobile and unknown locations of the User Equipment (UEs) add further difficulties to interference management in uplink spectrum where this uplink spectrum is a separate range from downlink for LTE FDD and the same range but on specific time slots for LTE TDD. Since the major source of this interference is the high power transmission from UEs, located in neighboring cells but far away from their serving eNodeBs, limiting this power can be greatly helpful. To mitigate interference in uplink spectrum by reducing power transmission from those UEs, a scheme is proposed in this paper for HetNets. The proposed scheme shifts the handover boundary from its conventional location for UEs, performing data transfer only in uplink. It can additionally help increase the battery life for these UEs and also, it limits a drop in uplink data rate due to clipping off power transmission level by the UE capability. Simulation has been performed to demonstrate the reduction in uplink power transmission in the proposed scheme.

Vehicular Ad Hoc Networks (VANETs) are selforganizing, self-healing networks which provide wireless communication among vehicular and roadside devices. Applications in such networks can take advantage of the use of simultaneous connections, thereby maximizing the throughput and lowering latency. In order to take advantage of all radio interfaces of the vehicle and to provide good quality of service for vehicular applications, we developed a seamless flow mobility management architecture based on vehicular network application classes with network-based mobility management. Our goal is to minimize the time of flow connection exchange in order to comply with the minimum requirements of vehicular application classes, as well as to maximize their throughput. NS3 simulations were performed to analyse the behaviour of our architecture by comparing it with other three scenarios. As a result of this work, we observed that the proposed architecture presented a low handover time, with lower packet loss and lower delay.

Il cinema di Hong Kong del nuovo millennio, a partire dal ritorno alla Cina nel 1997 per arrivare ai giorni nostri: dopo i fasti dell’epoca di Bruce Lee e le onde lunghe di John Woo e Wong Kar-wai, la settima arte hongkonghese si rinnova, svecchiando il “parente” cinese e guidandolo nella sua sfida a Hollywood. Gli autori, avvalendosi di interventi inediti dei più importanti registi e attori del cinema cantonese e dei critici più illustri, realizzano per la prima volta in Italia un volume completo su uno tra i fenomeni cinematografici più importanti del XXI secolo.

Next generation wireless networks demand a seamless mobility with resource utilization. The IEEE 802.16e specification was developed to address mobility within WiMAX networks. Link triggers provided by IEEE 802.21, Media Independent Handover (MIH) framework enable higher layers to initiate HandOver (HO) related activities in advance. Since performance of a wireless network is closely related with the execution timing of HO, an efficient HO trigger time selection algorithm is required to generate the link triggers at appropriate time. However, the determination of HO initiation time in mobile WiMAX networks is a challenging task. In this paper, we present a novel approach for HO trigger time selection in different propagation and mobility environments. The numerical and simulation results show that by triggering Link events at appropriate time, the link failure probability and probability of false handover initiation may be reduced in WiMAX networks.

Physical properties of wireless channels make very difficult or sometimes impossible to maintain open client sessions for interactive multimedia services. Short term client sporadic and not previsible disconnections lead to service interruptions which provoke a user headache especially if a firm real time multimedia service is used and a hard error when a real-time service (e.g. vigilance) is used. Also, during handover process channel conditions deteriorate leading to data loss. With multimedia services, handover influences packet loss, this is avoided by handover prediction mainly. Many handover prediction strategies use Received Signal Strength Indicator (RSSI) as the basic indicator for disconnection. Filters like Kalman and Grey Model (GM) are used by many researchers to estimate the RSSI value. These filters adapt rapidly the prediction to the continuous RSSI. This means that they can not work with short disconnections. In this paper we present a new RSSI Gradient predictor and filter technique capable of controlling short disconnections efficiently. The RSSI Gradient filter has been theoretically tested supporting well a long set of random Mobile Client (MC) movements inside the coverage area where coverage holes can be considered novelty.

In eras of great political turmoil, censorship becomes the weapon of those in power to suppress dissent that might empower the oppressed into revolting against them. Knowledge and access to it are easily two of the most obvious things to censor, as is art and literature. In the advent of technological advancements, technology became a serious contender against regimes and their struggle to maintain the monopoly on political power; expression quickly became easier through new avenues like television and film, and as national borders became less and less porous, despite the restrictions that governments imposed on filmmakers and artists, it became just as easy for transnational actors to consume material that was originally for the local.

Providing high capacity and cost effective backhaul is a looming challenge for mobile industry. In a packet-switched wireless communication system such as in the Third Generation Partnership Project (3GPP) Long term Evolution (LTE), data packets are forwarded between base stations (BSs) during handover over the bachhaul. The Packet Data Convergence Protocol (PDCP) of the source base station (BS) is responsible for forwarding the data packets to the target BS. The paper analyses, evaluates and improves the packet forwarding handover mechanism by reducing the amount of forwarded data between BSs. The performance criteria considered for evaluating these techniques include the PDCP buffer size at the source BS, the uplink Radio Link Control status load and the user object bit rate. We found frequent User Equipment (UE) polling by the packet network during handover helps in considerably reducing the unacknowledged PDCP data packets, and thereby reduces the amount of packet forwarding data, as the source BS has upto-date information of the UE reception state.

In September 2014, thousands of people started occupying different areas of Hong Kong, demanding "true democracy," ushering in what was known as the "Umbrella Movement." Two years earlier, Tatming Pair, an influential electronic formation, in a series of concerts, vented their worries, frustrations, and anger over the future of the city, giving voice to a deafening sense of disquiet. This article reads this performance as foreboding these upcoming political protests, attesting to the close alliance between the cultural and the political. It shows how popular music, in word, sound and image, both reflects, as well as impacts on, the city of Hong Kong.

The Internet research community has proposed many routing protocols to support efficient multicast application. However, these protocols were developed for multicast parties whose members are topologically stationary, and they thus do not support both mobile receivers and mobile sources. Unfortunately, the mobility of the multicast source is a challenging problem to solve. When a multicast source moves from one IP network to another, it obtains a new IP address. However, since IP multicast is receiver-initiated, and the multicast delivery tree is constructed based on the multicast source’s address, the multicast traffic cannot be delivered to multicast receiver unless a new delivery tree is built. As a consequence, the multicast routing entities require new multicast routing states and multicast receivers need to be notified whenever the handover occurs. This induces a non-transparent mobility, and leads to session disruption. To overcome these drawbacks, this paper presents a new solution to make multicast source mobility transparent to both multicast receivers and on-tree multicast routers. This solution, called Mobility-aware Rendezvous Point, extends the PIM-SM Rendezvous Point with mobility awareness, and introduces new techniques for the source registration with the Rendezvous Point. Simulation results have proved that the solution avoids the reconstruction of a multicast tree after the handover of the multicast sources.