Description:

Supplemental Downlink (SDL) has been enabled in Release 9 as part of the evolution of High Speed Downlink Packet Access (HSDPA). While the serving carrier (cell) for an HSDPA UE is part of paired spectrum, the SDL carrier is part of unpaired spectrum in a different band. Thus, SDL operation helps efficiently utilize unpaired spectrum for HSDPA. Release 10 extends SDL operation by bonding up to 3 carriers in the unpaired band with the serving carrier(s) in the paired band. In this paper, we focus on Release 9 SDL performance. The SDL carrier just needs to support the Primary Common Pilot Channel as overhead, thereby leaving a larger share of power for HSDPA channels. For these reasons, SDL deployments can provide significant gains in both the user experience and number of users supported for a given user experience, when compared to a Single Carrier (SC) deployment.