Wireless networks - Lecture 25: 1st review. The main topics covered in this chapter include: introduction to wireless networks; multiple access; quality of service (QoS); cellular concept; frequency reuse; locating co-channel cells; channel assignment strategies; handoff strategies;...
Wireless Networks Lecture 25 1st Review Dr Ghalib A Shah Last Lecture Cdma2000 introduction New MAC and Physical layer features Physical layer of cdma2000 Reverse Physical channels New Network elements in cdma2000 ► Packet Control Function (PCF) ► Packet Data Serving Node (PDSN) Mobility Management Handoff ► Intera-PCF ► Inter-PCF/Intra-PDSN ► Inter-PDSN Lecture - Introduction Part I I II III IV V The Wireless vision Radio Waves Channel Capacity Signal-to-Noise Ratio EM Spectrum Lecture - Introduction Part II Wireless Transmission ► Baseband signal, carrier frequency, fundamental frequency ► antenna size must correspond to signal’s wavelength • MHz signal few 100 m-s high antenna; • GHz signal few cm-s high antenna Encoding/Modulation Noises ► Thermal, Intermodulation, Crosstalk, Impulse Losses/Gain Lecture – Introduction Part III Multiplexing Transmission Mediums ► Guided, Unguided Propagation modes ► Ground wave, Sky wave, LOS Multi-path propagation ► Reflection, Diffraction, Scattering Fading Lecture – Error part I Transmission Errors Parity Check Cyclic Redundancy Check Block Error Code Lecture – Error part II Block Codes ► Hamming ► BCH (Generalization of Hamming) ► Reed Solmon (Subclass of non-binary BCH) ARQ ► Sliding window ► Go-back-N Lecture – Multiple Access (Part I) FDMA TDMA CDMA Random Access ► ALOHA ► Slotted ALOHA ► Reservation-based ALOHA Lecture – Multiple Access (Part II) CSMA ► Versions of CSMA ► CSMA/CA Spread Spectrum ► Frequency Hoping ► Direct Sequence Lecture – Evolution Part I 1G wireless cellular networks ► NMT ► AMPS ► TACS 2G cellular systems ► ► ► ► GSM IS-136 PDC IS-95 10 Lecture 12 – Cell Concept Part II Channel Assignment Strategies Handoff Strategies ► When to handoff ► 1G, BS based ► 2G or todays, Mobile-Assisted Prioritizing Handoff ► Guard channels concept ► Queuing handoff requests Practical handoff considerations ► Umbrella cell ► Cell dragging 17 Lecture 13 – Cell Concept Part III Interference and system capacity ► Co-channel interference and capacity ► Adjacent channel interference and capacity Channel Planning for Wireless System 18 Lacture 14 – Cell Concept Part IV Trunking and Grade of Service ► Measuring Traffic Intensity ► Trunked Systems • Blocked Calls Cleared • Blocked Calls Delayed ► Erlang Charts Improving Coverage and Capacity ► ► ► ► Cell Splitting Sectoring Repeaters for Range Extension Microcell Zone Concept 19 Lecture 15 - AMPS AMPS introduction System Overview Call handling Air interface Supervisory signals N-AMPS 20 Lecture 16 GSM GSM Introduction GSM System Architecture GSM Network Areas Specifications Subscriber Services Mobility 21 Lecture 17 – GPRS (part I) Introduction to GPRS GPRS Architecture Registration and Session Management Routing Scenario in GPRS Channels Classification 22 PDP Context Activation MS SGSN GGSN Activate PDP Context Request PDP type,PDP Address QoS Requested,Access Point,… Security Functions Create PDP Context Request PDP type,PDP Address QoS Negotiated,Access Point,… Activate PDP Context Accept PDP type,PDP Address QoS Negotiated,… Create PDP Context Response PDP type,QoS Negotiated,… 23 Lecture 18 – GPRS part II GPRS Protocol Architecture ► ► ► ► MS – BSS BSS – SGSN SGSN – GGSN GGSN – PDN GPRS Air Interface Data Routing and Mobility Uplink Data Transfer Downlink Data Transfer QoS in GPRS 24 Lecture 19 - IS-95 IS-136 CDMA/IS-95 Advantages ► ► Drawbacks ► Self-jamming, near-far problem, IS-95 Forward Channels ► ► ► ► Higher capacity, Improves voice quality (new coder), Less power consumption (6-7 mW) Privacy, graceful degradation Pilot Channel Sync Channel Paging Traffic IS-95 Reverse Channels 25 Lecture 20 - EDGE EDGE Introduction Modulation and Coding Schemes Link Adaptation and Incremental Redundancy Capacity Planning 26 Lecture 21 – UMTS / WCDMA part I UMTS Service Classes in UMTS ► Conversational, Streaming, Interactive, Background UTRAN Architecture ► RNC (Serving, Drifting) Radio Interface protocol Architecture Protocol Models for UTRAN Logical Channels 27 Protocol Model for UTRAN UTRAN protocol structure is based this model For all signalling activities in the network, it includes RANAP, RNSAP, NBAP protocols Trans Of all userspecific data CS or PS through user plan 28 Lecture 22 - WCDMA Part II Spreading and Scrambling Channel Concept ► Logical Channel (RLC) ->Transport Channels (MAC)->Physical Channels (PL) Physical Layer Procedures ► RACH Operation (Preamble of 16 symbols and wait for ACK on AICH) ► Cell Searching (256 chip primary Synch, 15 SSCs ► Power Control • • Fast Closed loop (1500 Hz TPC, Closed Loop 29 Lecture 23 - WCDMA Part III Compressed mode measurements Handover measurements ► Intra-mode ► Inter-mode ► Inter-system WCDMA packet data access Transport channels for packet data ► Common, dedicated, shared Packet scheduling algorithms ► Time division scheduling ► Code division scheduling ► Transmission Power-based scheduling 30 Lecture 24 - CDMA2000 New MAC and Physical layer features Physical layer of cdma2000 Reverse Physical channels New Network elements in cdma2000 ► Packet Control Function (PCF) ► Packet Data Serving Node (PDSN) Mobility Management Handoff ► Intra-PCF ► Inter-PCF/Intra-PDSN ► Inter-PDSN 31 ... ► Intera-PCF ► Inter-PCF/Intra-PDSN ► Inter-PDSN Lecture - Introduction Part I I II III IV V The Wireless vision Radio Waves Channel Capacity Signal-to-Noise Ratio EM Spectrum Lecture - Introduction... Transfer Downlink Data Transfer QoS in GPRS 24 Lecture 19 - IS-95 IS-136 CDMA/IS-95 Advantages ► ► Drawbacks ► Self-jamming, near-far problem, IS-95 Forward Channels ► ► ► ► Higher capacity,... Frequency Hoping ► Direct Sequence Lecture – Evolution Part I 1G wireless cellular networks ► NMT ► AMPS ► TACS 2G cellular systems ► ► ► ► GSM IS-136 PDC IS-95 10 Lecture – Evolution Part II