Adaptive Transmission WindowControl forDownlink Packet Transmission inCDMA Cellular Networks
Abubaker Khumsi, Katsuhiro Naito · 2006
Thispaperproposes anadaptive transmission Toavoid this shortcoming, alocation-based TPWC scheme windowcontrol scheme based onsoft handoff status andtrafficfordownlink transmissions in CDMA cellular packet loadtoenhance thesystem performance. Theproposed scheme communication systems wasproposed (6). Inthis scheme, the constrains thedownlink packet transmissions inCDMA cellular downlink transmissions arecontrolled according tothe systems byemploying atransmission windowforeachmobilechannel conditions andthelocation ofthemobile stations. station. Thetransmission windowsize iscontrolled byusing the Thiswasachieved bymaintaining almost thesamesizeof optimumthreshold valueforeachtraffic loadpoint. This transmission windowforallthemobile stations. Thisscheme optimum threshold value isselected withregard tothemobileimproved thedelay performance andgeographical unfairness. locations andthetraffic load. Computer simulations showthat However, theselected threshold values whichconstrain the compared withtheconventional schemes theproposed scheme transmission windowarenotoptimum forall traffic loads. improved thedelay performance andfairness ofservice inpacket Thispaperproposes an adaptive transmission window receptionh control fordownlink packet transmission inCDMA cellular reception. networks. Thegoal istoimprove thetransmission delay and thegeographical unfairness intransmission quality. Inthis r 1 1* 1 1 1* * * ~~~~~the transmission powerrequired forthepacket transmission to powerfromthebasestation andthemobile station inan themobile station isless than athreshold ThtxPtxave *AThtx, efficient manner. Moreover, automatic repeat request (ARQ),where Ptave istheshortterm average ofthetransmission site selection diversity transmission powercontrol (SSDT) l3) power Ptxand3Thtx isa threshold value. Withthis andmulti-user diversity (4)havebeenalsoinvestigated for pweadownlisa thesolvale. Wihahs improving th caact intedwln fclua mechanism, thedownlink cap acity7 canbeincreased because cmprommuniaion systems. capacityinthedownlinkofcelloftheinterference suppression duetothereduction inthe Formunica t applications whih. d nota transmitted power.However, thedisadvantage oftheTPWC requirements sucasd sice,thale transmissions scheme istheadditional transmission delay duetothe