Performance evaluation of a network synchronization technique for CDMA cellular communications

With enormous development in the field of communication, the atmospheric exposure of electromagnetic radiation from mobile base station antenna and its associated health hazards have now led to the growth of public concern for human exposure to Electromagnetic field (EMF) and its various health effects. Mobile communication antennas, mounted on the base transceiver station (BTS), are designed to radiate in a directional pattern into highly populated zones. The whole biological systems of our environment are now affected due to electromagnetic radiation from BTS in its surroundings. The prime objective of this study is to investigate the variation of power density and electric field in the vicinity of mast at different distances and height from two individual BTS situated at separate locations and the trend of the received radiation exposure level was analyzed.

The number of users accepted by a cell is limited by the total received interference power at base station transceiver in code-division multiple access (CDMA) system. In this paper, we propose a received power based call admission control (MSRP-CAC) scheme supporting multi-class services for uplink, which determines the admission of multi-class services via presetting power allocation ratios. The improved scheme is investigated and its performance is compared with simple scheme. Simulation results show that the improved scheme can guarantee the QoS of different traffic adaptively and improve the resources utilization. Keywords-call admission control; CDMA; power; uplink; service

The introduction of cellphones with poor receiver sensitivity, known as dirty devices, to the Code Division Multiple Access (CDMA) cellular network results in a reduction in cell edge coverage, degraded capacity, and higher drop-call rates. This poor network performance has a negative impact on customer experience and satisfaction, which may result in increased churn for CDMA wireless carriers. Previous research on the impact of dirty devices has used computer-based simulations. This paper demonstrates the influence of dirty devices on a live commercial CDMA network using two distinct approaches. The first approach deploys dirty and non-dirty devices in a live commercial cell, and measures the impact on forward base transceiver station (BTS) power and forward link Ec/Io (Ec is the received pilot chip energy and Io is the spectral density of the total power seen by the device). A series of tests on a live CDMA network with known dirty devices shows an increase in BTS transmit power resources compared with non-dirty devices, leading to the degradation of forward link Ec/Io. The second approach uses a statistical study of the aggregated pilot strength measurement messages reported by the mobile to ascertain the impact of known dirty devices on the overall network Ec/Io of non-dirty devices.

This paper surveys some of the traditional sequence designs that have been considered for code-division multiple-access (CDMA) communications. The design criteria are based on periodic and partial-period cross-correlation properties of the sequence sets. Variations of the design criteria are suggested here which are related more directly to CDMA system performance.

The stability of the telecommunications system infrastructure, particularly in the area experienced disastrous, should be restored as soon as possible to recover communication services. One solution for the recovery is by implementing a mobile Base Transceiver Station (BTS), which can be installed easily. In this work, an analysis of Arrow type Combat mobile BTS is conducted in the area of Terbanggi Agung, Central Lampung. The performance measurement and data analysis are performed on the three sectors of the cell coverage. The Received Total Wideband Power (RTWP), Call Completion Success Rate-Packet Switched (CCSR-PS) and Call Completion Success RateCircuit Switched (CCSR-CS) are taken at regular intervals (per hour for 24 hours), based on the standard Key Performance Indicator (KPI) of the International Telecommunication Union (ITU). The results showed that the average value of RTWP on each sector is 105 dB, while the value of CCSR-PS and CCSR-CS are above 95%. Moreover, the measured value of RTWP are less than the standard, which is assumed due to interference from neighbour BTS uplink frequency, despite the possibility of interference was small. In overall, the RTWP values, the CCSR-PS and CCSR-CS meet the standards of the ITU-T Recommendation E.850. Keywords: mobile BTS, received total wideband power (RTWP), call completion success rate- packet switched (CCSRPS), call completion success rate-circuit switched (CCSR-CS)

The Global Positioning System (GPS) is a spread-spectrum system that employs direct-sequence spreading of the spectrum to achieve better ranging accuracy. Although GPS was originally conceived for use by the military in their missions, it has become an important utility for a number of civil and commercial applications. To facilitate improvement in the use of satellite navigation by the civilian users, for example aviation and terrestrial transportation systems, an additional signal called L5 is being added to the current GPS L1 signals. L5 is also a spread spectrum signal in which the spreading code rate is ten times the coding rate of the current coarse acquisition (C/A) codes on L1. Also, the code period is ten times longer than the L1 C/A codes. Higher coding rates and longer code periods are expected to help overcome some of the shortfalls of the C/A codes. An important consideration in the design of a spread-spectrum signal for code division multiple access (CDMA) applications such as in GPS is to select codes to minimize what is known as CDMA noise. The code selection process can be very tedious, depending on the number of codes needed and the number of codes available in a given code set. Code balance, autocorrelation sidelobe peak, cross-correlation peak, and spectral line distributions are some of the measures available in the code selection process, and these measures are not necessarily independent. In this paper we give the details of the code properties and the selection process used in our study. The suggested process can be applied to code selection in any other spread spectrum system

This paper applies wireless communication technology using 2.4 GHz frequency in marine field to support Vessel Monitoring System, where it sails on the island and marine field that are not getting signal coverage from Base Transceiver Station (BTS) on land. Applying of Long Range (LR) WiFi with 2.4 GHz frequency is used as an extension of cost- effective data service on maritime wireless communications. Updates are in Long Range WiFi which is permanently on island or buoy so that can be shared by vessels in particular fishing vessels to transmit important information relating shipping activities such as vessel positions via Global Positioning System (GPS) on a mobile phone. The result is the system that can extend data connection up to 8 km.

Code division multiple access (CDMA) or multicarrier CDMA (MC-CDMA), Walsh-Hadamard codes are extensively used for its attribute of orthogonality and hence it leads to good cross-correlation property. In the last time, in CDMA communications, spread spectrum codes is Walsh-Hadamard codes and it is generated simply. Walsh-Hadamard codes are completely orthogonal binary user codes, that arehaving a lot of favorable applications in communications based on synchronous multicarrier. However, the optical applications of Walsh-Hadamard codes are also important for optical CDMA. To achieve this goal, all-optical Walsh-Hadamard codes generation using Mach-Zehnder interferometer (MZI) is explored in this paper.

In recent years, the joint decoding of combined source and channel coding have shown the capability of delivering performances exceeding that of separately decoded schemes. In this paper, a well-known joint source/channel coding scheme is investigated for possible use in future 4th Generation (4G) direct sequence spread spectrum multiple access (DS/SSMA) code division multiple access (CDMA) communication systems. Due to the availability of potentially large sets of sequences with good correlation characteristics, the DS/SSMA CDMA system considered in this paper employs complex spreading sequences (CSS). A multiuser CSS-based DS/SSMA CDMA communication system was implemented as test platform for the joint source/channel coding scheme. Several families of CSSs, including Zadoff-Chu (ZC), double sideband constant envelope linearly interpolated root-of-unity filtered general chirp-like (DSB CE-LI-RU Filtered GCL), analytical bandlimited complex (ABC) and quadriphase (QPH) sequences are investigated on this platform. Simulated bit error rate (BER) performances are presented for uncoded, separate source and channel coded and joint source/channel coded systems under realistic multipath fading channel conditions.

In this paper we present how computer simulation can be used to estimate the mean output power and the probability cumulative distribution function of one base station output power in GSM. The basis of the method is adding the simulation of random distance between the mobile station (MS) and base transceiver station (BTS) to the known method of telephone traffic simulation. The simulation is a suitable method for the estimation of base station output power, especially in the case when it is not easy to calculate the output power's dependence on these factors. A couple of numerical examples present the results of these simulations.

Recent statistics show an increase in environmental disasters, a fact which is also perceivable to the public as reports of avalanches, earthquakes and landslides mount in media coverage. Search and Rescue with modern localization techniques consequently attracts attention from scientific and industrial sides. This paper introduces one part of the I-LOV project, endorsed by the German Federal Ministry of Education and Research. In this project partners from relief organizations, universities and industry investigate enhancements to disaster handling and victim rescue. One possible option is to take advantage of the fact, that a lot of people own a mobile phone today. To locate a person by his or her mobile phone requires to take over the phone by an own Base Transceiver Station (BTS). Jamming all other networks is one option to achieve that. This paper will introduce a new Field Programmable Gate Array (FPGA) based jamming system which consumes little power and disturbs only small parts of the GSM spectrum but reliably cuts all connections between mobile stations (MS) and existing BTS.

A mathematical matrix formalism which combines network management system (NMS) statistics from Cosmote GSM land mobile radio network and MOS measurements derived from drive tests are used, in order to extract a derivative MOS key performance indicator. Initially, the calculation is performed in a base station controller (BSC) area and then base transceiver stations (BTS) MOS distribution patterns are examined for different speech encodings. Examples of speech encoding effectiveness evaluation are performed using the previous speech encoding distribution patterns. Moreover, the effect of mobile station (MS) technology on different speech encodings is pointed out. Ultimately, different speech encodings are compared using quality and speech codec distribution patterns.

CDMA (code division multiple access) is a promising air interface technique for digital cellular systems. The soft handoff between base stations is one of many important features of CDMA for the mobile station crossing the cell boundaries. When a mobile station during a call moves to an adjacent MSC (mobile switching center) service area, we propose that the traffic data from the new base station be carried to the old MSC through the link between MSCs. The old MSC receives multiple traffic data from the base stations that are serving the mobile station requesting the inter-MSC soft handoff. We develop an analytical approach for calculating the traffic load on the link by the soft handoffs between MSCs. The service area of an MSC is defined as the union of the service areas of the base stations and is assumed to have a hexagonal shape. The blocking probability of the soft handoff between MSCs due to the shortage of the link capacity is derived by the Erlang loss formula.

For developing telematics devices, traditional development methods include the unit function test, compatibility test and T-Car, which have some limitations. Telematics devices have various functions that require accounting for the interactions among three major elements of automotive electronics: the vehicle, the device unit and driver. The KAAS (KATECH Advanced Automotive Simulator) system is a virtual-reality-based test environment designed to test and analyze the three elements in one place. One of the difficult functions when constructing such VR (Virtual Reality)-based telematics test environment is to develop a test method for the LBS (Location-Based Service) function such as a car navigation demanding the GPS (Global Positioning System) satellite signals because KAAS is in a fixed laboratory. To overcome these problems, a real-time GPS simulation system, which can be integrated with KAAS, is needed because the location of the vehicle in virtual space is determined purely by the driver’s personal intention while driving virtually. This paper presents new concepts needed to construct a VR-based telematics test environment to generate a GPS RF signal, which reflects the continuously changing vehicle location during virtual driving in real-time. To construct this system, the coordinate transform must be conducted from a rectangular coordinate system that is compatible with a virtual 3D DB that is used to construct a 3D image for KAAS using a WGS84 and a longitude-latitude coordinate system compatible with a GPS simulator. Moreover, the real-time HILS (Hardware In Loop Simulation) systems and the CDMA (Code Division Multiple Access) simulation system are developed to evaluate telematics devices. Finally, we show its applications and results.

In this treatise, the performance of Code division multiple access (CDMA) system is investigated using multi-user transmitter pre-processing (MUTP). The MUTP is promising signal processing technique which is carried out at the transmitter side to reduce the burden of detector and hence low complexity receiver is made feasible at mobile station (MS) in the context of downlink (DL) communication. Further, the unique signature sequence is considered to support more user population. In particular, the performance of MMSE-MUTP assisted CDMA system is investigated for realistic channel specifications based on Stanford University Interim (SUI) channel model. It has been demonstrated that the MMSE-MUTP assisted CDMA system provides achievable bit error rate with low complexity of receiver for DL transmission.