Performance comparisons of power allocation mechanisms for downlink handoff in the WCDMA system with microcellular environments

Comparison of Downlink Power Allocation Mechanisms in Soft Handoff for the WCDMA System with Heterogeneous Cell Structures

“…To manage resources during downlink soft handoff is actually the issue of allocating power from multiple cells to a user. In the literature, different downlink power allocation techniques have been proposed, such as EPA [20], QBPA [11], SSDT) [6], and LPPA [21]. In the following, we denote q i , i , and L i as transmission power, the received SIR and the link gain from base station i in an active set ϒ , respectively.…”

“…The link proportional power power allocation (LPPA) technique was suggested in [21]. According to LPPA, the transmission power of a base station during handoff should be proportional to the link gain between the handoff user to its serving base stations.…”

“…In this section, we detail how LPPA can be implemented in an iterative manner and the convergence of the iterative LPPA algorithm will be proved in Appendix I. As mentioned in [21], the principle of LPPA is to allocate more power to a link with better quality among the active set. Assume that all serving base stations in the active set ϒ allocate power q i,h for user h. Denoteq i as the maximal allocation power for an individual user in cell i, and (q i,h ) as the received E b /N o from cell i.…”

“…Staehle et al [18] proposed two proportional power allocation methods, in terms of transmission power and target signal quality. In our previously proposed link proportional power allocation (LPPA) technique [21], the base station with better link quality will be responsible for allocating more power to the handoff user. It was shown that LPPA can alleviate the power exhausting issue for the microcellular CDMA system.…”