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Cross-Provider Cooperation for Network-Based Localization
Published in Chao Gao, Guorong Zhao, Hassen Fourati, Cooperative Localization and Navigation, 2019
Among various networking technologies, global system for mobile (GSM) communications is an attractive option for positioning because it is a popular standard for cellular phones and has widespread infrastructures around the world [15–18]. A typical GSM phone is served by only a single network provider according to the inserted subscriber identification module (SIM) card. In recent years, the technology for the development of mobile devices has progressed tremendously. The dual-SIM mobile phones have been developed so that users can incorporate two SIM cards into one handset. These phones can connect to multiple networks and allow users to separate private and professional calls, or to select the most cost-efficient network. This cross-provider architecture should enable a future computing environment. From the viewpoint of network-based localization, connecting a mobile device to multiple operators makes it possible to combine multiple location estimations from different network providers. When location estimations from multiple providers are available, combining their individual advantages can achieve better performance than any individual provider, and can avoid selecting a poorly-performing network provider. However, the cross-provider information is still unexplored for localization. Although previous studies present some hybrid positioning schemes, most of them focus on the signal or model combination [19–24].
Wearable Communication and IOT Systems Basics
Published in Albert Sabban, Wearable Systems and Antennas Technologies for 5G, IOT and Medical Systems, 2020
GSM is a cell phone standard called Global System for Mobile Communications. GSM provides standard features like phone call encryption, data networking, caller ID, call forwarding, call waiting, short message service (SMS) and conferencing. GSM cell phone technology works in the 1900 MHz band in the United States and the 900 MHz band in Europe and Asia. GSM phones use a subscriber identification module (SIM) card to store the subscriber’s information, such as phone number and other data, that proves that a user is in fact a subscriber to that carrier. Several cellular phones need a SIM card in order to identify the owner and communicate with the mobile network.
Systems
Published in W. Bolton, Higher Engineering Science, 2012
As an illustration of a system involving digital signals, consider the mobile telephone system. Figure 11.12 shows the basic elements of such a system.For transmissionThe speech input to the microphone gives an analogue signal which is converted into a digital signal by the analogue-to-digital converter. This is then coded in the vocoder, i.e. the binary representation of the signal has its format and bit ordering organised, to give a suitable serial binary signal which is used to modulate a radio frequency carrier for transmission.For receptionThe received signal from the aerial is a binary modulated radio frequency carrier and is amplified, filtered, demodulated and decoded to provide the wanted signal in digital form. A digital-to-analogue converter (DAC) is used to provide an analogue output for the loudspeaker.DiallingThe microcontroller in the SIM card has a digital input from a keypad for the dialled number. This is then transformed into a suitable digital signal by the analogue-to-digital converter (ADC) in the processing module. It also provides an output to a display to give a visual display of the dialled number and other messages. The SIM card stores, in digital form, such data as the directory number of the user, subscription information and data to determine access to the network. A mobile telephone cannot access the network service unless it can provide a valid access code to enable the network to authenticate the user.
NomadicBTS: Evolving cellular communication networks with software-defined radio architecture and open-source technologies
Published in Cogent Engineering, 2018
Emmanuel Adetiba, Victor O. Matthews, Samuel N. John, Segun I. Popoola, Abdultaofeek Abayomi
The SDR software back-end comprises of the Soft Base Station Subsystem (SoftBSS) and the Voice over Internet Protocol Private Automatic Branch Exchange (VoIP PABX) software running on a single-board embedded computer or PC with an Operating System (OS). The SoftBSS provides the necessary interconnection between the SDR front-end hardware and the VoIP PABX. SoftBSS implements a software transceiver which performs functions such as frequency tuning, Gaussian Minimum Shift Keying (GMSK) modulation and demodulation, clock synchronization, control command transaction as well as transmission of receive and transmit bursts. It also implements the Session Initiation Protocol (SIP) mapping functions in order to establish SIP connections for processing by the VoIP PABX. For instance, the International Mobile Subscriber Identity (IMSI) stored on the Subscriber Identity Module (SIM) card of a Mobile Station (MS), which is the end-user phone, is presented to the VoIP PABX as an SIP client. The location of the MS is mapped to SIP registration, call connection is mapped to SIP transactions, while Short Message Services (SMS) function is realized through instant messaging extension to SIP (Apvrille, 2011). The SoftBSS, as shown in Figure 1, also contains a Graphical User Interface (GUI) to provide access for configuring the NomadicBTS by technical administrator in a user-friendly manner. As a proof of concept, the SoftBSS was realized, in this present study, using a combination of open-source technologies such as Ubuntu Linux, OpenBTS and GNU Radio (Burgess & Samra, 2008; Reyes et al., 2016).
Security challenges in the transition to 4G mobile systems in developing countries
Published in Cogent Engineering, 2023
Fanuel Melak Asmare, Lijaddis Getnet Ayalew
Additional security enhancements were introduced in 4 G LTE. Further layers of abstraction were added, for example, in terms of the unique identifiers (ID) for an end-mobile device (UE). In 2 G, a single unique ID was used on the SIM card; in 3G and later 4 G LTE, temporary ID and further abstraction were used, resulting in smaller windows of opportunity for identity theft. Another mechanism for increasing security in 4 G was the addition of secure signaling between the UE and the MME (Mobile Management Entity; Bargh et al., 2007).