Dragan Mitić

Calculation of the Mean Output Power of Base Transceiver Station in GSM

In this paper we calculate the distribution of output power of traffic channels of base station in GSM network depending on the traffic load. The principle of the calculation is to find the distribution of the output power of one traffic channel, and then to combine this distribution with the distribution of the number of busy traffic channels. Numerical example refers to the simplest distributions, but the principle can be implemented on the more complicate distributions.

Calculating the Required Number of Bits in the Function of Confidence Level and Error Probability Estimation

This paper proposes the calculation of the required number of bits transmitted in the system, in order to achieve the desired level of confidence. Proposed solution is based on the selected value for the bit error probability, and statistical confidence levels. In addition, required error probability for telecom- munications protocols and data transfer protocols is discussed, overview of the BER (Bit Error Ratio) testing equipment performance is provided, and compro- mise of testing time in relation to the statistical level of confidence depending on BER is examined.

Influence of Intra-cell Connections on the Traffic Calculation of Radio Resources in Mobile Network

Abstract In this paper we analyze the influence of the connections between users, belonging to the same cell, on the increase of traffic loss. The utilization of Erlang model in this case gives underestimated loss. We calculate some simple examples in the case of GSM. Several numerical examples prove that traffic loss increases with the increase of intra-cell traffic in total traffic and with the increase of the number of channels in the group. The results are confirmed by the computer simulation.

Comparison of the Influence of Intra-cell Traffic and Finite Number of Mobile Phones on the Determination of Number of Channels in the BTS of GSM Network

Abstract In this paper we compare the influence of intra-cell connections in GSM network and the influence of the limitation of the number of traffic sources in one GSM cell on call blocking. It is proved that the influence of intra-cell connections on the loss probability is larger than the influence of limited number of traffic sources. The results are obtained by calculation and by simulation.

The Influence of Short Error Clusters on CCS No 7 Link Availability

Summary We observe the Common Channel Signaling (CCS) No 7 link availability under short error bursts or clusters with high bit error rate (BER), and compare it to the availability of CCS No 7 link under equivalent random errors. It is shown that the mean time to changeover of the CCS No 7 link in the case of error clusters is greater than in the case of random errors of same intensity. The reason for this positive impact of short clusters with high BER is the concentration of more than one errored bits in one errored signal unit. In the same time the mean alignment time of CCS No 7 link (that is out of service) is shortest if errors are grouped in rare short error clusters. Hence, the availability of CCS No 7 link increases and frequency of CCS No 7 link oscillations decreases, if errors are grouped.

Traffic Simulation of GSM Cells with Half–Rate Connection Realization Possibility

Abstract This paper presents simulation model for the analysis of characteristics of base station, which may establish half-rate connections. Accuracy of realized simulation model is analyzed comparing its results to a number of corresponding results, which are obtained by calculation or presented in referenced literature. These corresponding results are obtained, in the first case, analytically, solving the system of equations, which are modelling the system and, in the second case, from the literature, which deals with the similar systems. At the end, simulation model is implemented to analyze in detail several systems with different total number of traffic channels. The results of simulation pointed out how much probability of connection loss decreases in the case of great traffic load, when half-rate connections realization is implemented.

Influence of Mobile Users’ Density Distribution on the CDMA Base Station Power

Abstract In this paper we analyze the influence of users’ density distribution in one cell of CDMA mobile network (ie adjusted power control on the forward link) on base station emission power. This influence is analyzed for different circles radii around base station within which same emission power is generated for all mobile users, and for different values of propagation loss coefficient. It is proved that emission power in this cell must be increased comparing to the similar cell, which uses complete power control. The power increase is greater when greater number of users are situated near base station, and for greater values of propagation loss coefficient. The results are presented, illustrated by numerical examples and verified by simulation for three users’ density distributions: uniform, decreasing and increasing density from the base station to the cell rim. The simulation process, which is based on random traffic process, is presented briefly.

Comparison of two methods for subchannel seizure in gsm cell using vamos technics

Abstract This paper considers two methods for voice channel seizure in one GSM cell, which uses VAMOS technics for traffic efficiency improvement. An important characteristic for models comparison is call loss caused by unsuccessful connection pairing in one timeslot. The first method gives priority to voice connection quality, and the other one to traffic efficiency. The methods are estimated by the simulation, which is first tested by comparing its results to the calculation results for a very small system. The influences of traffic intensity, allowed power difference of two paired connections and attenuation coefficient on the loss caused by unsuccessful pairing are assessed.

Influence of user density distribution on the pairing probability in GSM cell with implemented VAMOS technology

ABSTRACT In this paper, we present the influence of user density distribution in the base station cell on the (un)pairing probability and on the loss caused by the lack of idle traffic resources in GSM systems, which use VAMOS technology. The influence of user distribution is analysed together with the influence of environmental attenuation coefficient and allowed power difference in emission power between two signals, which are paired. It is pointed out that decreasing user density from the base station towards the cell edge is less favourable when considering total loss than it is for uniform and increasing user density. It is further presented to what extent the total loss in the system with the implementation of VAMOS technology is greater than the loss in the classic Erlang traffic model with the same traffic characteristics.

Analysis and Application of FLL based on the Processing of the Input and Output Periods

This paper describes development, analysis, implementation and application of one recursive Frequency Locked Loop (FLL) based on the measurement and processing of the periods of the input and output signals. FLL is the linear discrete system of the first order, which regulates its output once per the input period. The FLL parameters are defined by the frequencies of three clocks. These frequencies have to be mutually in defined relationship for the stable FLL. FLL provides a wide range of properties useful for different applications. The stability and the other conditions, under which the described system can have the properties of a FLL, are investigated using the Z transform analyses. Using mathematical analyses and the simulations of this FLL it is shown that, for the corresponding system parameters, FLL possesses the power noise rejection ability. This FLL can also be used for the different predicting and tracking applications, for the measurements of the frequency of the input signal in the noise environments and for the other applications. The oscilloscope picture of the characterized input and output signals, recorded on the realized FLL, is presented.