Visitor Location Register Research Articles

Interstate Migration in India During the COVID-19 Pandemic: An Analysis Based on Mobile Visitor Location Register and Roaming Data

In migration and mobility studies, the availability of scientifically reliable data remains a persistent challenge. The recent move towards harnessing mobile and big data has also been unable to resolve the data issues due to accessibility, privacy, as well as ethical and methodological intricacies involved with such data sets. In this paper, we explore a new set of data known as visitor location register (VLR) and roaming data, which is recorded and reported by mobile service providers. The reporting model of VLR data used and presented in this paper is not only free from privacy and ethical concerns but also methodologically sound and simple to compute as compared to any previous approaches. Drawing on VLR data, this paper finds direct evidence of unusually high interstate net reverse migration during the first and second COVID-19 lockdowns in India (44.13 and 26.3 million, respectively), and thereafter quick return migration back to cities during unlocks. The findings from this paper also provide insights into evolving migration directions, precarity, pockets of origin and destination and state policies in containing reverse migration during lockdowns in India. We anticipate that the data presented in the paper have the potential to fill a major data gap in migration and mobility studies in other countries too if VLR and roaming data are made available at the required spatial and temporal levels.

Optimal management of distance-based location registration using embedded Markov chain

In this study, we deal with a Distance-Based Registration with Implicit Registration, which is an enhanced scheme of the Distance-Based Registration in mobile-cellular networks. In comparisons with other Location Registration schemes, various studies on the Distance-Based Registration scheme and performance have been performed. However, a real network hierarchy has not been properly reflected in the performance evaluation of the Distance-Based Registration. To accurately evaluate the registration and paging costs of the Distance-Based Registration, a real network hierarchy should reflect that a mobile network is made up of many Visitor Location Register areas. Furthermore, we use an embedded Markov-Chain model in the Visitor Location Register hierarchy, which can reflect not only the Implicit Registration effect of the outgoing calls of user equipment but also cell staying time of the user equipment that may follow a general distribution. Without consideration of the Visitor Location Register, the paging cost decreases due to a small paging area, but the location registration cost rises because of frequent inter Visitor Location Register. The numerical results according to the various conditions show an accurate evaluation of the Distance-Based Registration performance in a real network hierarchy and the general cell staying time. Generally, the total signaling cost will increase when we consider the Visitor Location Register. However, for more appropriate evaluation of the Distance-Based Registration performance, it is necessary to consider the Visitor Location Register hierarchy.

Minimising network cost by employing sliding window method at mobile switching centres in GSM network

The cost effort of a global system for mobile communications (GSM) network is to be minimised for meeting effectively and efficiently the service requirements of ever increasing mobile subscriber's base. The period of temporary storage of subscribers' profiles in visitor location register (VLR) at a mobile switching centre (MSC) affects the cost of GSM network. This research study proposes a sliding window method for determining the storage period of profiles in VLR that minimises the network cost of GSM network. Further, this study examined and evaluated the computational efforts on proposed method. The proposed method proves to be better than the reported set intersection method.

Minimising network cost by employing sliding window method at mobile switching centres in GSM network

The cost effort of a global system for mobile communications (GSM) network is to be minimised for meeting effectively and efficiently the service requirements of ever increasing mobile subscriber's base. The period of temporary storage of subscribers' profiles in visitor location register (VLR) at a mobile switching centre (MSC) affects the cost of GSM network. This research study proposes a sliding window method for determining the storage period of profiles in VLR that minimises the network cost of GSM network. Further, this study examined and evaluated the computational efforts on proposed method. The proposed method proves to be better than the reported set intersection method.

Secure Delegation-Based Authentication for Telecare Medicine Information Systems

The telecare medicine information systems (TMISs) enable patients to gain health monitoring at home and obtain medical services over mobile networks. In recent years, many authentication schemes have been proposed to address the security and privacy issues in the TMISs. For example, Kim et al. and Huang et al. proposed efficient delegation-based authentication protocols by using elliptic curve cryptography. These protocols have a prerequisite that both the home location register and the visited location register must share secrets beforehand. In this paper, we show that Kim et al. ’s and Hwang et al. ’s schemes are vulnerable to known key attacks. Moreover, they fail to provide communication confidentiality. We then present a new secure delegation-based authentication protocol by using the identity-based cryptography. The proposed protocol removes the weaknesses of the above-mentioned protocols. Through the analysis of the Burrows-Abadi–Needham logic, along with a random oracle model, we demonstrate that the proposed scheme provides secure authentication. In addition, the proposed scheme can provide more security functionaries than the existing delegation-based authentication protocols. Better tradeoff among security and functionality features and communication and computation costs makes our scheme suitable and applicable in the TMISs.

Supervised machine learning techniques in cognitive radio networks during cooperative spectrum handovers

Cognitive communication model perform the investigation and surveillance of spectrum in cognitive radio networks abetment in advertent primary users (PUs) and in turn help in allocation of transmission space for secondary users (SUs). In effective performance of regulation of wireless channel handover strategy in cognitive computing systems, new computing models are desired in operating set of tasks to process business model, and interact naturally with humans or machine rather being programmed. Cognitive wireless network are trained via artificial intelligence (AI) and machine learning (ML) algorithms for dynamic processing of spectrum handovers. They assist human experts in making enhanced decisions by penetrating into the complexity of the handovers. This paper focuses on learning and reasoning features of cognitive radio (CR) by analyzing primary user (PU) and secondary user (SU) data communication using home location register (HLR) and visitor location register (VLR) database respectively. The SpecPSO is proposed for optimizing handovers using supervised machine learning technique for performing dynamic handover by adapting to the environment and make smart decisions compared to the traditional cooperative spectrum sensing (CSS) techniques.

‘Mobile Ping Data’ – Metadata for Tracking

In this paper Professor Reg Coutts and Hugh Selby explain the current technology and associated data available to assist with monitoring the location and movement of mobile devices. Their paper describes the source of Visiting Location Register (VLR) data and how it can be used to infer ‘trajectory’ of mobile phones and other mobile devices when they are switched on and when there is no call activity and hence no associated Call Charge Records (CCRs). The authors examine the potential of VLR data to provide greater insight into the movement of mobile devices of interest enhances the capabilities of law enforcement to build a case. Index words: Australia, Mobile devices, Telephone, SIM, tracking, records, proof of location

Historical based location management strategies for PCS networks

Due to the current popularity of wireless communication, personal communication service networks have attracted a lot of attention. As mobile terminals (MTs) in such networks have the ability to communicate on the move, location management (LM) is a critical issue that should be handled carefully. Managing MTs locations is to simultaneously perform two main operations, which are; location update and paging. A good LM strategy maintains both operations with the minimum time and signaling penalties. Although several LM strategies have been introduced, they still suffer from several drawbacks. This paper introduces three novel LM strategies, which are; historical based location management (HBLM), direction based location management (DBLM) and trajectory based location management (TBLM). TBLM strategy is based on geographical position of MTs, while HBLM and DBLM are based on geographical position of MTs as well as time aspects. Visited locations are saved in MT's internal cache in the form of cell identifier as well as the corresponding time interval. Location tracking is fully supervised by the MT's current visitor location register (VLR). On the other hand, the collected location information in MT's cache is sent to VLR when MT passed through a previously defined number of cells or when a previously defined number of time periods has elapsed. In HBLM, paging is done according to the historical movements saved in VLR, while DBLM takes also MT's movement direction into consideration while in TBLM, paging is done according to the historical trajectories that MTs are used to follow. Experimental results have shown that the proposed LM strategies significantly improve MTs' tracking process as they introduce the minimum signaling penalty (for paging and registration) with an acceptable paging time delay compared with recent LM strategies.

Analysis of movement-based registration considering network architecture and general cell residence time

This study considers movement-based registration (MBR) with implicit registration, an improved version of original MBR. In order to obtain more accurate registration cost of the MBR, we consider real network architecture in which a mobile network is composed of visitor location registers (VLR), a group of cells. We show that, when the network architecture is considered, the location registration cost increases but the paging cost decreases compared to the case that the network architecture is ignored. Furthermore, we propose an imbedded Markov chain model to reflect call holding time and cell residence time of a mobile station (MS) that may follow a general distribution. Numerical results for various situations are shown to analyze the exact performance of MBR under real network architecture.

An optimal sliding window size for maximising GSM network throughput

The throughput of a Global System for Mobile Communications (GSM) network is to be maximised for effectively and efficiently meeting the service requirements of the ever-increasing mobile subscriber base. The period of temporary storage of subscribers' profiles in the Visitor Location Register (VLR) at a Mobile Switching Centre (MSC) affects the throughput of a GSM network. This research study proposes a sliding window method for determining the storage period of profiles in the VLR, and the principle of optimisation for such a policy is to maximise the throughput and minimise the call set-up time in a GSM network.

An Improvement on An Efficient Mobile Authentication Scheme for Wireless Networks

Mobile communication network has brought us great convenience. However, network security issues are outstanding increasingly. Authentication is the most essential procedure for preventing illegitimate, unauthorized or insecure devices from making access to the network. Tang and Wu proposed an efficient mobile authentication scheme for wireless networks, and claimed the scheme can effectively defend all known attacks to mobile networks including the denial-of-service attack. This paper strengthens the security of the scheme by authenticating the identity of visited location register such that any adversary cannot obtain the communication key between a mobile user and a service provider, or prevent them from establishing this key. An improvement is proposed to remedy these flaws. Our design is a less strong requirement for a mobile user MS in the communication cost than that of Tang and Wu's. DOI: http://dx.doi.org/10.11591/telkomnika.v11i10.3706

Elliptic Curve Cryptography in Securing Networks by Mobile Authentication

This paper proposes an enhanced authentication model, which is suitable for low-power mobile devices. It uses an Extended Password Key Exchange Protocols (2) and elliptic-curve-cryptosystem based trust delegation mechanism to generate a delegation pass code for mobile station authentication, and it can effectively defend all known attacks to mobile networks including the denial-of-service attack. Moreover, the mobile station only needs to receive one message and send one message to authenticate itself to a visitor's location register, and the model only requires a single elliptic-curve scalar point multiplication on a mobile device. Therefore, this model enjoys both computation efficiency and communication efficiency as compared to known mobile authentication models.

Performance Analysis of Existing Location Management Scheme with its Variants in PCS Network

This paper is presenting a comparative study of existing location management scheme with its various variants in Personal Communication Services (PCS) network. The existing location management scheme is based on two tier database architecture; Home Location Register (HLR) and Visitor Location Register (VLR).In the existing location management scheme, there is a single HLR. In the HLR, profile of a Mobile Terminal (MT) is permanently stored. The VLR caches the profile of the MT from the HLR when it is providing the service to the mobile terminal. Mobile terminal, on move changes its location and comes under the Registration Area (RA) of new VLR. The MT profile should be removed from the VLR from where this MT is coming from and the HLR should have the information of current location of the MT. In the existing location management scheme this is done by the explicit deregistration scheme. In the existing call delivery procedure of PCS network, the HLR is always consulted to get the current location of the MT. This call delivery procedure supports an idea that is it necessary to inform the VLR that MT who was residing in its RA is now in the RA of another VLR? This paper has used other de-registration schemes as: Implicit deregistration, Polling de-registration, Timeout de-registration scheme and Group de-registration scheme in the variant of existing location management scheme. The single HLR architecture is prone to bottleneck and multi HLR architecture for PCS network is proposed for the efficient call delivery. Analysis done in this paper shows that we can significantly reduce the location management cost in the various variants of the existing location management schemes. This paper finally concludes that group de-registration scheme when implemented with the proposed multi HLR architecture gives better results.

Hybrid Scheme with Adaptive Replication and Mobility Anchoring Point (MAP) in Wireless Networks

Replication strategy is mostly useful for replicating the mobile user's profile at selected locations from which some callers have higher calling rate. Location management scheme also include replication strategy to reduce the location lookup cost of called mobile user. It plays important role in personal communication services in order to reduce call setup cost, call setup time, and increases the QoS (quality of service). In prior replication schemes, called user's location profile is placed at some fixed and limited number of visitor location registers (VLRs) based on call history of the caller. In prior hybrid schemes location update and replication strategies are combined together. These prior hybrid schemes apply pointer forwarding strategy and replication. But these schemes have limitations like holding "loose" form of location profile and higher location update cost. We have proposed a new hybrid scheme which includes adaptive replication of updated user's location profile and mobility anchoring point (MAP) for location update. The main objective of the proposed scheme is to reduce call setup cost and call setup time. In order to achieve the objective, adaptive replication is applied at certain visitor location registers (VLRs) according to movement of caller. The replica is kept updated at MAP and replicated to neighbor VLRs as per movement of the caller. We have presented fluid-flow based analytical modeling which shows that proposed scheme outperforms the prior hybrid scheme.

Double Delegation-Based Authentication and Key Agreement Protocol for PCSs

Many protocols have been proposed for solving the user authentication in portable communication system. One of the schemes is based on the delegation concept. Home Location Register (HLR) delegates Mobile Station (MS) to be authenticated by Visitor Location Register (VLR). The main drawback of the scheme is that the HLR is required during the online authentication phase between VLR and MS. In this paper, a double delegation-based authentication and key agreement protocol is proposed. The main advantage of our protocol is that this scheme requires only MS and VLR online. This protocol will thoroughly utilize the proxy signature features to facilitate the operation of this protocol while only requires two members (MS, VLR) to be online at the same time.

Time Based Location Management using CACHE Scheme for Mobile Environment

Location management refers to the problem of updating and searching the current locations of mobile nodes in a wireless network. The location administration basically is performed by using two registers, HLR (Home Location Register) and VLR (Visitor Location Register). The current location information has to be maintained efficiently in location registers for effective call delivery. In the system it is difficult to deliver a call to the users at an optimal time interval. This is used to manage and reduce the level of time of call forwarding from the caller to the callee. To make it efficient, the sum of update/lookup costs of a location database must be minimized. To reduce the cost of location database, this paper we are using the concept of time based location administration system. This paper proposed the CACHE scheme which register the user's frequent movement of repeated visit of same location and maintain the user's detail up-to-date. This optimizes the time-interval which minimize the location administration cortical factors to be established.

Sliding window method based on enhanced throughput prediction for improving GSM network efficiency by reducing HLR-VLR transitions

The throughput of a global system for mobile GSM communications network is to be maximised for meeting effectively and efficiently the service requirements of ever increasing mobile subscriber's base. The period of temporary storage of subscribers' profiles in visitor location register VLR at a mobile switching centre MSC affects the throughput of GSM network. This research study proposes a sliding window method for determining the storage period of profiles in VLR that maximises the throughput of GSM network. The proposed method proves to be better than the existing set intersection method.

Performance Analysis in Dynamic VLR based Location Management Scheme for the Omni Directional Mobility Movement for PCS Networks

Location management plays an important role in guaranteeing the effective operation of Personal Communication services (PCS). In this paper a dynamic VLR (visitor location register) based location management is introduced for PCS networks. In this, MSC gathers the details about mobile terminals (MT) and performs location registration. This scheme is analytically examined for Omni directional movement of MTs and also it reduces the location management cost.

User's Profile Replication Tree and On Demand Replica Update in Wireless Communication

Replication strategy is mostly useful for replicating the called mobile user's profile at selected locations where some caller mobile users have higher calling rate. It plays important role in personal communication services (PCS) in order to reduce call setup cost and call setup time. In prior replication schemes, replicated sites (visitor location registers) have no inter relationship. We have proposed a novel and innovative replication tree which is buildup from replicated VLRs (visitor location registers). VLRs are replicated based on effective replication probability of caller mobile user. Home location register (HLR) keeps update replica at root VLR in the replication tree and root VLR forwards update replica to a VLR in the replication tree on demand. The main objective of the proposed scheme is to reduce call setup time and call setup cost by enabling replication of called mobile user's location profile at certain visitor location registers (VLRs) where caller mobile user roams. We have presented analytical modeling which shows that setting inter-relationship among the replicated sites helps in further reducing the call setup cost.

User Informatics Optimized Search and Retrieval-Congestion Avoidance Scheme for 4G Networks

The objective of 4G network is to provide best services to the users which in turn made the performance of existing network more critical. Further, the large traffic generated in such networks creates congestion resulting in overloading of the system. Frequent delays, loss of packets, and in addition the number of retransmission/paging also increases the computational cost of the system. This paper proposes a novel way to reduce overloading and retrieval mechanism for VLR through optimized search, based on the information of users mobility pattern (User profiles based (UPB)) to track the user. This not only improves the overall performance of the system, especially in the events when the visitor location register (VLR) is overloaded due to heavy traffic and congestion of the network. It was also established through simulation studies that the proposed UPB scheme optimizes the search and reduces the average waiting time in a queue. In addition, the provision of VLRW (waiting visitor location register) avoids the overloading of main VLR and provides a recovery/retrieval mechanism for VLR failure.