الفهرس 
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Abstract
Location awareness in gen¬eral is emerging a tremendous interest in different fields and scopes. position is the key element of context awareness. Although Global positioning System (GpS) produces an accurate position, it requires an open sky and does not work indoors. It is obvious that GpS provides most accurate positions; it is commonly used with navigation applications and some of emergency applications. Moreover, some of the traffic analysis applica¬tions use GpS-enables smart phones as probes for traffic data collection. Since GpS requires a line of sight to the satellite and not all the phones are equipped with GpS, more attention has been given to other alternatives like Wireless Fidelity (WiFi). It is commonly used in the ur¬ban and sub-urban areas, hot spots are everywhere. WiFi has been used for localiza¬tion in many researches and commercial applications.
However, WiFi-based localization techniques address sev¬eral challenges but unfortunately not all the cellular phones are equipped with WiFi. Hence, Global System for Mobile Communications (GSM) based localization techniques appear again. GSM represents about 85% of today’s cell phones. GSM consumes minimal energy if compared to WiFi and GpS. After the revolution of the smart phones and the development of the mobile applica¬tions, some approaches have been implemented, especially those who use accessible parameters from operating systems and do not require any modification on the software or hard¬ware layer. Most of these approaches use parameters like Received Signal Strength (RSS) and Time Advance (TA).
GSM-based phones are also used in traffic monitoring services as dynamic probes or Floating Car Data (FCD). In a default scenario, when Mobile Entity (ME) moves around in the GSM network, it is unavoidable to change between different geographical areas. To know which cell the ME should communicate with, the ME constantly listens to the signals sent out from the different (Base Transceiver Station) BTSs. The signals are measured at certain threshold values of the signal strengths, the ME will decide that it needs to change its serving cell and initiates what is called by a handover (HO) procedure. To measure the different signals, the ME stores information about the currently serving cell, as well as up to six other cells of which it has received the strongest signals, called neighbour cells. All these information are stored in Network Measurements Report (NMR), which is sent to the core network every 480 millisecond in active (in call or data transfer) mode. However, core network can receive same NMR in idle mode by sending paging message to UE.
This thesis presents a set of mobile positioning techniques and methodologies, which can be applied on different types of handhelds. Each technique focuses on one concept like the accuracy, availability or dependency and tries to address the challenges that are faced by the similar system. This thesis also considers using the GSM-based phones as probes for traffic estimation which includes a set of important principles like the travel direction detection, speed estimation, sampling mechanisms and privacy concerns. All the techniques have been practically tested in Egypt roads by using the commercial smart phone and the results concluded were compared to the latest approaches in similar environments.