Performance Evaluation of Soft Handover in WCDMA System

In this paper soft handover parameters in WCDMA system are investigated. They include the effect of imperfect power control on the downlink capacity and power assignment to the mobile station, the micro diversity gain which represents the gain in the downlink direction, and the macro diversity gain which represents the gain in the uplink direction. The results showed that the power control error increases the total power consumption by the mobile station which leads to decrease the capacity (number of users per cell). Soft handover decreases the fade margin which leads to improve the coverage area. During soft handover the mobile station needs lower signal to noise ratio compared with no soft handover to obtain the specific bit error rate. Keyword: Cellular Mobile System, Soft Handover (SHO), Power Control. ماظن يف ةسلسلا ةلقانملا ءادأ مییقت WCDMA ةلوصف ظیفح ناوفص دوجوملا دبع يماس روتكدلا ةیئابرھكلا ةسدنھلا مسق / لصوملا ةعماج ةصلاخلا ثحبلا اذھ يف مییقت مت ماظن يف ةسلسلا ةلقانملا تلاماعم .WCDMA ریثأت لمشت تلاماعملا هذھ ةرطیسلا ا ریغ یلاثمل ة ل ةعسلا ىلع ةردقل ةیسیئرلا ةطحملا نم)لزانلا لاصتلاا يف BS ةلقنتملا ةطحملا ىلإ MS صیصختو ( ةردقلا ةلقنتملا ةطحملل MS ةیلخلا نم عونتلا بسك نإ ، وركاملا بسكلا لثمی يذلاو ا يف لزانلا لاصتلا بسك كلذكو عونتلا و لاصتلاا يف بسكلا لثمی يذّلا دعاصلا ملا ةطحملا نم) ةلقنت MS ىلإ ةیسیئرلا ةطحملا BS .( ترھظأ جئاتنلا نإ ةردقلا ىلع ةرطیسلا يف أطخلا يدؤی ىلإ يف ةدایزلا ةردقلا كلاھتسا ل ةیلكلا ةطحمل ةلقنتملا ) MS ( و يدؤی يذلا لكل نیمدختسملا ددع) ةعسلا لیلقت ىلإ لا (ةیلخ ةسلسلا ةلقانملا . للقت امم توفخلا شماھ يدؤی ىلإ ةقطنم ةدایز .ةیطغتلا للاخ ةسلسلا ةلقانملا لقا ءاضوضلا ىلإ ةراشلإا ةبسن ىلإ جاتحت ةلقنتملا ةطحملا ناف .ددحم أطخ لدعم ىلع لوصحلل ةسلس ریغ ةلقانم عم ةنراقم Received: 2 – 12 2010 Accepted: 22 – 2 – 2011 Al-Rafidain Engineering Vol.19 No.6 December 2011 2