3GPP Broadband Evolution to IMT-Advanced - 4G Americas

example, HSUPA) operating in a Release 5 mode. This flexibility assures the maximumdegree of forward- and backward-compatibility. Note also that most UMTS terminalstoday support GSM, thus facilitating use across large coverage areas and multiplenetworks.Once deployed, operators can minimize the costs of managing GSM/EDGE and UMTSnetworks, because these networks share many of the same aspects including:Packet-data architectureCell sitesAntenna systemsBackhaul circuitsSubscriber account managementService platformsUsers largely don’t even need to know to what type of network they are connected,because their multimode GSM-HSPA (and eventually GSM-HSPA-LTE) devices canseamlessly hand off between networks.The changes being planned for the core network are another aspect of evolution. Here,the intent is to reduce the number of nodes that packets must traverse. This will result inboth reduced deployment costs and reduced latency. The key enabling technology is EPC,which is described in detail later in this paper.The upgrade to LTE will be relatively straightforward, with new LTE infrastructure havingthe ability to reuse a significant amount of the UMTS-HSPA cell site and base stationincluding using the same shelter, tower, antennas, power supply and climate control.Different vendors have different, so-called “zero-footprint” solutions allowing operators touse empty space to enable re-use of existing sites without the need for any new floorspace.An operator can add LTE capability simply by adding an LTE baseband card. New multistandardradio units (HSPA and LTE), as well as LTE-only baseband cards, aremechanically compatible with older building practices, so that operators can use emptyspace in an old base station for LTE baseband cards, thus enabling re-use of existing siteswithout the need for any new floor space, as mentioned previously.Base station equipment is available for many bands including the 1.7/2.1 GHz AWS bandand the recently auctioned 700 MHz bands in the US. In 2010, operators and vendorsbegan LTE deployment.On the device side, multi-mode chipsets will enable devices to easily operate acrossUMTS and LTE networks. For example, one chipset vendor has announced a series ofchips that support the following combination of technologies: UMTS, HSPA+ and LTE; EV-DO Rev B; and UMTS, HSPA+, EV-DO Rev B and LTE. 31One important and interesting aspect of technology deployment is that an advancedtechnology such as LTE enables operators to upgrade prior technologies, such as HSPA.Examples include:31 http://www.qualcomm.com/press/releases/2008/080207_Qualcomm_to_Ship.html.Transition to 4G: 3GPP Broadband Evolution to IMT-Advanced, Rysavy Research/3G Americas, Aug 2010 Page 30