Site-Specific Assessment of Node B using Key Service Quality Indicators over 3G/UMTS Networks from Outdoor Drive-Test Measurements

Periodic service quality monitoring of a deployed cellular communication network by means of an innovative expert-driven field test analysis provides an in-depth understanding of the status and performances of the network as well as of the statistical behaviour of the user population. Such knowledge allows for a better engineering and operation of the whole network, and specifically the early detection of hidden risks and emerging troubles. In this paper, an experimental performance assessment of Node B based on key quality parameters considered for design, planning and network optimization was carried out via drive test at Ugbor avenue, BIU Campus and Gapiona avenue, all located in G. R. A, Benin City. It was established that the Ec/lo range measured for BEN 035 (BIU) indicates that the BS will be able to support services demanded by more subscribers accessing the network. Proper tuning is required on this BTS to eliminate the possibility of noise interference by this BS on nearby BSs when the loading is low. It was discovered that the QoS is very poor in the environs of BEN026, with the result that UEs will not be able to access data due to rapid data rate decreases, network login difficulty, difficulty in call initiation, no network, and high call drop rate. Hence the CPICH power level should be adjusted so that base station can provide service to users; however this does not guarantee that the interference caused by other nearby base stations is within the acceptable range to establish the session. At BEN 098 (Gapiona avenue) the Ec/lo is below the standard which is -9 dB for data which low means the QoS at Gapiona avenue is very poor and can only serve for voice calls with no data capacity whatsoever. The bond between RSSI/RSCP and Ec/Io performance at the different measurement locations of Node B were also assessed. It was observed from the results that Ec/Io degrades when RSSI/RSCP decreases. Degrading Ec/Io can be an indication of increased other cell interference which will also increase the need for downlink traffic power

Radio Field Strength Propagation Data and Pathloss calculation Methods in UMTS Network

The design of future-generation mobile communication systems depends critically on the pathloss prediction methods and their suitability to various signal propagation regions.  An accurate estimation of radio pathloss is useful for predicting coverage areas of base stations, frequency assignments, determination of electric field strength, interference analysis, handover optimization, and power level adjustment. The radio path loss will also affect other elements such as the required receiver sensitivity, the form of transmission used and several other factors. As a result, it is necessary to understand the reasons for radio path loss, and to be able to determine the levels of the signal loss for a given radio path. In this paper, we investigated the radio signal path attenuation behavior, by conducting an experimental measurement survey in a UMTS network transmitting at 2100MHz band in Government Reservation Area (GRA), Benin City. The measured field strength data collected at various distances from the base stations was used to estimate the pathloss. Firstly, the effect of different parameters, such as distance from base stations was studied and it is observed that path loss increases with distance from the signal source due to a corresponding decrease in field strength. Secondly, the calculated pathloss data have been compared with data from other existing pathloss prediction methods. We find that the Okumura-Hata model pathloss values were closest of all the propagation models considered classifying the environment into consideration. Thus, the performance of Okumura-Hata model shows its suitability for path attenuation loss prediction in UMTS networks in GRA