The IUP Journal of Telecommunications
The Impact of Shadowing During Soft Handoff Process in the Downlink Direction of WCDMA Communication Networks

Article Details
Pub. Date : Nov, 2018
Product Name : The IUP Journal of Telecommunications
Product Type : Article
Product Code : IJTC21811
Author Name : Shalini Aggarwal, S Dixit and Alok Aggarwal
Availability : YES
Subject/Domain : Telecommunications
Download Format : PDF Format
No. of Pages : 12

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Abstract

Code Division Multiple Access (CDMA) systems are interference limited systems and the level of interference directly relates to the capacity of the system. Shadowing plays a vital role in interference. CDMA uses Soft Handoff (SHO) technique for a smother transmission while moving from one cell to another. The paper investigates and evaluates power allocation during SHO on two fronts, one with shadowing component and the other without considering the impact of shadowing. A two-way SHO case has been considered for the analysis purpose. When shadowing is not considered, more power is needed to support SHO in order to keep the same Eb/I0 target. When shadowing is considered, the attenuation of the radio channel is dynamically changing. To meet the same Eb/I0 target, the power that needs to be allocated should be changing as well. For the mobile users near the cell boundary with SHO, less average power is needed to meet the same Eb/I0 target. In the downlink direction, the inter-cell interference is closely related to the location of mobile user. Shadowing increases average interference level. SHO effects in the downlink interference are quite complicated, depending on the location of Mobile Station (MS), the radio attenuation and power division strategy. SHO decreases the probability of over-power and QoS deterioration for the users at the cell boundary. It also decreases the total average power needed by the MS at the boundary of the cell.


Description

Several developments have taken place during last three decades in mobile cellular networks starting from first-generation Advanced Mobile Phone System (AMPS) to fourth-generation Long-Term Evolution (LTE) technology, and we are becoming more mobile than ever. Third-generation (3G) systems are predominated by CDMA (Code Division Multiple Access) technology, which apart from traditional voice services also supports multimedia and Internet-based services. WCDMA (Wideband CDMA) is the most adopted 3G air interface where capacity of the system becomes more flexible as all users share the same spectrum allocation and use codes to uniquely identify one user from others.


Keywords

Handoff, Soft Handoff (SHO),Code DivisionMultiple Access (CDMA), Shadowing, Power control