The paper evaluates how the control of transmitted power affects the intensity of radiation in a mobile network cell. Cell models without power control, with standard power control and a model with ...power control and channel reallocation are considered. The relative reduction of radiation is evaluated and several examples of calculations are presented. Remarks are given on the dependence of radiation reduction on the number of traffic channels, traffic intensity and signal attenuation coefficient. The assessment procedure and results are based on previously verified traffic process simulation models.
In this paper we consider the network of mobile users where CDMA technique is used in cells. The dependence of disturbances/interference in the uplink direction as a result of surface user ...distribution in the neighbouring cells is determined. Three user distribution types are considered: the uniform one, decreasing from the cell centre to the rim and the increasing one. The interference calculation is performed using mean values of user distance from the cell centre. It is proved in the paper that interference caused by decreasingly and increasingly distributed users may differ from the interference caused by the cell with uniform user distribution by not more than ±75%.
This paper presents the simulation of mobile telephony systems realized in Excel program. Although primarily intended for other applications, Excel has several advantages over other specialized ...programs for simulation purposes. Excel application for simulation is illustrated by several examples from already published papers with the main goal to describe the most important part of realized simulations that allows determination of all important characteristics of telecommunication traffic process. Beside traffic process, the Excel application allows a reliable simulation of base station emission power starting from a random distance between the base station and mobile station.
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.
This paper analyzes the existing connection rearrangement in mobile telephony systems with implemented VAMOS techniques. The main objective of rearrangement application is to decrease connection ...unpairing loss when there is exactly one idle traffic subchannel (OSC) in the system. The rearrangement technique was well-known in old multistage switching systems, where it contributed to traffic loss decrease. It is proved in this paper that connection loss probability due to pairing inability is decreased when rearrangement is implemented. Connection realization is improved in following cases: when offered traffic is greater, when allowed emission base station power difference between two paired OSCs in channels is smaller and when greater channel groups are implemented. Results are verified by computer simulation and illustrated by a numerical example.
The output power of traffic channels in one cell of GSM like systems is
estimated in this paper. We consider the real case: the number of users is
much higher than the number of channels, the output ...power of one channel
depends on the cube of the distance between a mobile user and the base
station, and the distribution of users in the cell is uniform. We derive the
expressions for cumulative distribution of output power of one channel and
for the mean output power of the whole base station. Results of the
calculation are confirmed by computer simulation.
A mobile users’ network with power control on traffic channels, as it is GSM, is considered in this paper. It is analyzed the influence of busy channels reallocation on the necessary emission power. ...The main principle in reallocation is that users who need greatest power for their connections take traffic channels of the first carrier where power is always maximum. It is assessed that reallocation process is not more complicate than the simplest handover processes. It is proved that this method may be used to decrease emission power of carriers after the second one. Power saving depends on number of carriers, environmental propagation coefficient and users’ density distribution in the cell. The results are verified by originally developed simulation program.
In this paper the properties of handover traffic are analyzed in the system with channel reservation. The reservation of several traffic channels only for handover calls leads to probability of ...handover calls congestion decrease to the level of per mill or even lower. The congestion of all traffic channels in the neighbouring cells is the cause that handover traffic process deviates from the Poissonian distribution and this deviation is negligible, because handover calls congestion probability is very low. This low handover calls probability is also the reason why implementation of one equivalent cell instead of 6 neighbouring cells surrounding the central cell does not model satisfactory the traffic flow in the mobile network. The randomness of handover calls arrival to the central cell is tested by our originally developed simulation program. Coefficient of variation of time between handover calls arrival to the central cell is calculated as the result of simulation. We introduced the ratio of the coefficient of variation of the time between new handover calls appearance in the central cell to the value of this coefficient for surrounding cell as the measure of handover calls randomness: the nearer this ration to 1, the more random is handover calls arrival to the central cell.
In this paper we present the dilemma dealing with the choice of speech
segment duration and the calculation of speech signal quality in the packet
telephone network of Electricity supply industry ...(ESI). The analyzed signal
is packetized by one packet. The characteristic of this network is that
disturbances of long duration in power system produce burst packet loss. The
longer speech segments increase the packet delay, but decrease the number of
lost packets in one burst, and vice versa. Here we present why it is better
to choose speech segments of short duration. Also, we suggest the corrected
method for the calculation of speech signal quality in packet network under
the influence of long duration disturbances.
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