ECE Department Florida Institute of Technology Wireless Data Communication Networks Lecture 21: GSM evolution

ECE Department Florida Institute of Technology Outline  Evolution of GSM into a packet data network Page 2

ECE Department Florida Institute of Technology GSM Evolution path Page 3 GSM – migrates towards packet data networks with broadband access air interface Driver behind the migration – change in the use model for GSM networks

ECE Department Florida Institute of Technology Cellular data networks – throughput comparison Page 4

ECE Department Florida Institute of Technology GPRS Network Architecture Page 5  GPRS introduces new entities to support data packet transmissions  New entities are PCU, GSN, Border Gateway, and GPRS register

ECE Department Florida Institute of Technology GSM/GPRS – put together Page 6

ECE Department Florida Institute of Technology GPRS/EDGE – MCS and throughputs Page 7  GPRS and EDGE introduce multiple Modulation and Coding Schemes (MCS)  MCS allows different data rates through the GSM time slot  Selection of MCS depends on channel condition and capability of mobile  GPRS and EDGE allow for multiple slot aggregation  Slot aggregation allows increase in data rate offered to the user  EDGE introduces new modulation scheme – 8-PSK GPRS MCS EDGE MCS Note: EDGE supports both GMSK and 8- PSK PHY throughput for different MCS

ECE Department Florida Institute of Technology UMTS architecture Page 8 Acronyms: Node B = Base Station SGSN = Service GPRS Node GGSN = Gateway GPRS Node MSC = Mobile Switching Center VLR = Visitor Location Registry HLR = Home Location Registry Open Interfaces: Uu – W-CDMA air interface Iub – Node B to RNC Iur – between RNC Iu – between UTRAN and CN  W-CDMA air interface for UMTS radio Access  Air interface is based on CDMA access  Reuse of the existing GSM network architecture  Iub fully standardized  The core network allows both GSM and UMTS radio access

ECE Department Florida Institute of Technology UMTS Radio Interface Page 9 Air interface determines the performance of a cellular system W-CDMA – revolutionary change from GSM’s TDMA scheme Advanced radio resource management – required by diverse 3G applications Multi-rate spreading W-CDMA is interference limited Provides soft capacity and Coverage, capacity, quality tradeoffs DL TX Diversity, DL and UL RAKE receiver reception, UL space diversity Diversity support Coherent on both UL and DLDetection Open loop and closed loop with 1500 commands/secPower control 10msFrame Length 15,30,60,120,240,480, 960, 1920 kb/sec Up to 3 code aggregations Single code user rates DL(after coding) 15,30,60,120,240,480, 960 kb/sec Up to 6 code aggregation Single code user rates UL (after coding) Variable: UL (power of 2), DL(1-256)Spreading 3.84 Mc/secondChip rate 5MHzBandwidth DS-CDMA with FDD and asynchronous operationAccess scheme ValueProperty Summary of W-CDMA properties UL – Uplink, DL - Downlink W-CDMA Scheme

ECE Department Florida Institute of Technology Long Term Evolution (LTE)  LTE – 4 G technology  Changes in both radio access and core  Radio access is OFDM based (1.4-20MHz)  Core is packet only; Voice as VoIP  Simplified core – all IP  eNodeB responsible for RRM Page 10

ECE Department Florida Institute of Technology Review  List successor technologies to GSM  How is voice handled in GSM (as CS or as PS)  Which technology promises higher data rates: EDGE or HSPA?  What type of access scheme is used in UMTS?  What type of access scheme is used in LTE?  Does LTE core network contain switches?  How is voice handled in LTE?  Explain the concept of adaptive MCS Page 11