To this end, we study an analytical model for the WCDMA cell by taking into consideration the effects of the following: the multi-service environment, the soft blocking, the imperfect power control and multipath propagation. In this model, the maximum transmission power of a base station in the downlink is considered as the shared system resource. We solve the Markov chain and provide an efficient recurrent formula for the system occupancy distribution, as well as the so-called local blocking probabilities.
Based on them, we calculate the CBP of different service-classes accommodated in the cell, versus the total offered traffic load. We evaluate the analytical model through simulation.
The results show that the accuracy of the model is very satisfactory. In addition, we show the effect of the intra-cell interference due to orthogonality factor on the erlang capacity of the cell. Unable to display preview. Download preview PDF. Skip to main content. This service is more advanced with JavaScript available.
Advertisement Hide. Authors Authors and affiliations Ioannis B. Daskalopoulos Vassilios G. Vassilakis Michael D. Conference paper. This is a preview of subscription content, log in to check access. Holma, H. Kaufman, J. IEEE Trans. It is the physical reference for other channels. It is used for power control, transmission and coherent detection, channel estimation, measurement of adjacent cells and obtaining the scrambling code Scrambling Code SC [2].
Despite receiving a high power level, communication can be poor because of the interference effect. In these situations, UMTS is more tolerant than GSM, rather than producing a disconnection in communication leads to a reduction in transmission rate. This fact, however, produces an additional load on the radio channel.
Power level is divided into different paths which, depending on the quality of the Rake receiver included in the mobile phone , provide a greater or lesser number of signal components.
In the case of obtaining different signal delays delays , the orthogonality of the codes transmitted by a base station fades. This causes all the signals sent by the station, and in particular the signals from other subscribers, would have a high interference. Denotes the power measured by a receiver on a physical channel communications in particular. It is used as an indicator of signal strength as a criterion for delivery in the downlink control energy and for calculating path loss.
And can only be measured once the receiver has found the dominant pilot. This value is the one that has direct effects on bit error rate. Figure 1. Area under analysis. Measuring a WCDMA signal over the air, the antenna must be connected appropriately to the frequency band to be measured. In the UMTS cellular communication system denotes the power measured by a receiver in a specific communication physical channel. It is used as an indicator of signal strength as a criterion for delivery in the downlink control energy and the calculation of loss per path.
Figure 1 shows the area where measurements took place. This area covers approximately 0. Open area model includes scenarios with open space, and no large trees or buildings in the path [2].
In the field area located in the upper left side of Figure 1 , we have an open area because the presence of trees is very low and building is null. Figure 1 also shows the positions where the 4 nearest Base Stations are located. The suburban model represents a village or a road with scattered trees and houses, some obstacles near the mobile, but not too congested [2].
In this case, academic buildings areas were chosen because present a combination of low and medium buildings heights with some trees. With these features the multipath propagation analysis is very thorough, considering in this way the obstacles that cause mainly this phenomenon. The defined area for the analysis consists of 4 faculties with a mix of 9 administrative and teaching buildings equal space distributed, recreation areas, halls, one stadium, a library and a large teaching building that extends from North to South as shown in Figure 1 and delimited by the red square.
Also the closest Node Bs is shown in a blue circle with the 3G label. Kriging interpolation method [8] was used to get the coverage maps. All measurements were performed with the measuring equipment at a height of 1 meter and 10 cm above the floor and moving with him on foot through the exteriors of buildings [9]. While measurements were obtained, it was necessary to have geo-referenced information at the point where measurements were made.
This feature requires that the GPS antenna is outside and wait a few minutes to get traced back at least 4 satellites and be able to have the position information of latitude, longitude, altitude and time.
Kriging methodology [8] application running over MatLab requires of position information Latitude and Longitude plus one additional value to generate the estimations maps in two dimensions. In this case, the third values considered were the power of the Ec and CPICH, and their respective coverage maps were gotten. This paper shows the measurements for , and Scrambling codes.
The next section exhibits the results of the measurements described before. Figure 2. Coverage estimation map for Ec SC Figure 3. The Node B is located in the right bottom corner and its SC is , and The Antennas height for this Node B is about 18 meters. Node B is located in the right bottom corner of the Figures 2 and 3; we can see that the strength level of the WCDMA signal decreases when the measurement point is located further from the Node B.
The SC is the strongest signal in the studied area. The higher power levels are identified by the first band of color scale on the bottom of the image-white color.
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