LTE 基础一览.ppt

* * This diagram, taken from the Technical Specifications 36.300 shows the E-Utran, which contains a new network element, the evolved Node B. eNB. That provides the communications with handset or UE (User equipment. A new interface called X2 connects the eNBs, enabling direct communication between the elements and eliminating the need to funnel data back and forth through the RNC. X2 is used to support the mobility. The E-UTRAN is connected the EPC through the S1 interface, which connects the eNBs to the Mobility Management Entity (MME) and Serving Gateway (S-GW) elements through a “many to many “ relationship. No Macro diversity (Soft handover) for the flat structure. This is the drawback. * * Here we see SAE in conjunction with legacy systems. This is where the likes of WiMAX would be incorporated rather than earlier attempts to align the WiMAX and LTE air interfaces themselves which were not successful. UPE User plane entity * * Here is a slide that shows the linkages of all the standards. The technology evolution is downwards as spectral efficiency, Data rates and bandwidth increase We could spend a LOT of time on this single slide Starting of with the 2G based cdma technology is-95A and then evolving to B with Data as part of the release B 2.5 G compatible technology, the path to 3G follows by the C version of CDMA and then into the Data only 1xevdo for 3.5G giving good headline speeds and also two further evolutions through release A and B. UMB makes an appearance here as a 3.9G technology, having no precedent before it Next is GSM with evolution to GPRS then EGPRS or Edge and to Edge Evolution which is currently being defined as part of Release 8. Now edge evolution is A NATURAL EXTENSION OF AN EXISTING TECHNOLOGY which can skip a generation of evolution straight into 3.9G using a new modulation format ( 32 qam) and giving close to 2mb/S AS IT’S headline speed - Edge evolution: can use multiple carriers ( up to 4)with eight timeslots each, it nee