GPRS Air Interface aspects

Transcription

1 General Packet Radio Services (Placeholder for a cover picture; this picture should always cover the whole slide width as shown here) 21MAT MAR Re 08/00 Air Interface aspects 1 1 General Packet Radio Services

2 Your Lecturer is: Reiner Stuhlfauth Rohde&Schwarz Training Center, Munich 2 General Packet Radio Services

3 Outline of Presentation Structure of presentation General Packet Radio Services

4 T 3 Radio Interface Normal Burst F 57 data bits 26 Bits F 1 Training Sequence 1 57 data bits T 3 G 8,25 - Burst-Types T 3 T 3 Frequency Correction Burst 142 fixed Bits Synchronisation Burst 64 Bits 39 data bits Extended Training Sequence 39 data bits T 3 T 3 G 8,25 G 8,25 Dummy Burst T fixed Bits T 3 G 8,25 Access Burst T 8 41 Bits Training Sequence 36 data bits Abbreviations : T=Tail Bit (3 Bits/ 8 Bits in leading part of Access Burst F=Flag (1 Bit) G=Guard Period (8,25 Bits/ 68,25 Bits in Access Burst) T 3 G 68,25 uses the same Burst types as known from GSM 4 General Packet Radio Services

5 Radio Interface Radio Interface: Common Features to GSM needs Circuit Switched Signalling: FCCH, SCH and BCCH uses GSM Normal Burst for data transport: T Information F F Information T G Trainingssequence ,25 T = Tailbits F = Flagbits G = Guardtime uses same Modulation: GMSK 5 General Packet Radio Services

6 Capacity on Demand Capacity on demand: Provides circuit switched channels and packet switched channels in a dynamic manner Signalling: BCCH + FCCH + SCH + CCCH Circuit switched channels Packet switched channels PDCH Example: Cell with 1 Frequency channel: 1 physical channel for signalling, 4 physical channels for circuit switched TCH and 3 physical channels for packet switched PDCH 6 General Packet Radio Services

7 Physical Resource Mapping of TCH and PDCH on a frequency channel FN TN GSM TCH: Traffic channel in circuit switched mode, 26-Multiframe 12 x TCH S 12 x TCH Frequency channel I PDCH: 1 Radio Block = 4 Bursts PDCH: 1 Radio Block = 4 Bursts = 1 Frame PDCH: Traffic or signalling channel in packet switched mode FN = Frame number S = SACCH TN = Timeslot number 7 General Packet Radio Services

8 Physical Resource Reminder: Mapping of GSM-TCH on a frequency channel FN TN GSM TCH: Traffic channel in circuit switched mode, 26-Multiframe 12 x TCH S 12 x TCH Frequency channel I PDCH: GSM-TCH: PDCH: 1 Radio Block = 1 Radio Block = 1 Timeslot 4 Bursts in Uplink and 4 Downlink Bursts direction, using the 26 Multiframe = 1 Frame PDCH: Traffic or signalling channel in packet switched mode FN = Frame number S = SACCH TN = Timeslot number 8 General Packet Radio Services

9 Physical Resource Mapping of -PDCH on a frequency channel 1 Radio Block is the smallest transport unit in! 2 Radio Blocks may belong to 2 different users! => sharing of s TN PDCH: 1 Radio Block = 4 Bursts PDCH: 1 Radio Block = 4 Bursts Radio Block transmits signalling or data = 1 Frame TN = Timeslot number 9 General Packet Radio Services

10 10 Physical Resource GSM = 1 Timeslot on 1 Frequency Channel Downlink Uplink Symmetric data transfer General Packet Radio Services e.g. ARFCN + TN, using Temporary Block Flow to identify radio resource = N Radio Blocks (=4 Normal Bursts) on 1 or more Timeslots. Temporary Block Flow, TBF identifies allocated Downlink Uplink Downlink Uplink or downlink Symmetric data transfer Asymmetric data transfer uplink physical resource fixed dynamic Extended dynamic

11 Physical Resource TBF: A Temporary Block Flow is a physical connection used by two entities to transport Packet Data Units on a packet data physical channel. TFI: A Temporary Flow Identifier is assigned to every TBF. The TBF is identified by the TFI together with the direction. TBF = TFI + Direction 11 General Packet Radio Services

12 : Additional Logical Channels PDCH: Packet Data Channel: DL PBCCH Broadcast of packet data specific information Signalling and Control PCCCH DL UL DL PPCH PRACH PAGCH Paging MSs for packet data and circuit switched services MS initiates uplink transfer Resource assignment to an MS DL PNCH Notifying PtM Packet Transfer Packet PTCH PDTCH Packet Data Transfer; (multislot) Traffic Channels DL & UL PACCH Signalling: resource allocation, acknowledgements, PC, TA, etc. 12 General Packet Radio Services

13 Radio Interface Logical Channel Comparison CIRCUIT SWITCHED GSM FCCH SCH BCCH PCH CCCH RACH AGCH NCH SDCCH TCH SACCH SACCH FACCH PACKET SWITCHED No Direct Equivalent No Direct Equivalent PBCCH PPCH PRACH PCCCH PAGCH PNCH PDCH PCCCH/PACCH PDTCH PACCH PTCCH PACCH 13 General Packet Radio Services

14 Radio Interface Channel Combinations CIRCUIT SWITCHED (51 MFM) i) TCH/F + FACCH/F + SACCH/TF ii) TCH/H(0,1) + FACCH/H(0,1) + SACCH/TH(0,1) iii) TCH/H(0,0) + FACCH/H(0,1) + SACCH/TH(0,1) + TCH/H(1,1) iv) FCCH + SCH + BCCH + CCCH v) FCCH + SCH + BCCH + CCCH+SDCCH/4(0..3)+SACCH/C4(0..3) vi) BCCH + CCCH vii) SDCCH/8(0.7) + SACCH/C8(0. 7) viii) TCH/F + FACCH/F + SACCH/M ix) TCH/F + SACCH/M x) TCH/FD + SACCH/MD (52 MFM) xi ) PBCCH+PCCCH+PDTCH+PACCH+PTCCH xii ) PCCCH+PDTCH+PACCH+PTCCH xiii )PDTCH+PACCH+PTCCH 3 new channel combinations in whereccch = PCH + RACH + AGCH + NCH and PCCCH=PPCH+PRACH+PAGCH+PNCH. 14 General Packet Radio Services

15 : Signalling Information Signalling Information about Existence mandatory Existence optional Existence optional Circuit switched PDCH additional PDCH BCCH PBCCH PCCCH Complete Info or Pointer to PBCCH -Info, Signalling Additional -Info 15 General Packet Radio Services

16 : Signalling Information Complexity Broadcast Control Channel Common Control Channels Packet Broadcast Control Channel Packet Common Control Channels 16 General Packet Radio Services

17 + GSM Multiframes Multiframes used in GSM and 51-Multiframe: GSM-Signalling Multiframe: GSM-Traffic Multiframe: -Signalling and Traffic General Packet Radio Services

18 Multiframe 52 - Multiframe Structure for PDCH 52 TDMA Frames 1 Radio Block = 4 TS in consecutive TDMA Frames NB NB NB NB B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11X B0 - B11 = Radio Blocks T = Frame used for PTCCH X = Idle frame Uplink-Multiplexing: PDTCH & PACCH or PDTCH, PACCH & PRACH Downlink-Multiplexing: PDTCH & PACCH PDTCH & PACCH & PCCCH incl. PBCCH PDTCH & PACCH & PCCCH without PBCCH 18 General Packet Radio Services

19 Radio Interface Timing Advance on PTCCH 52 Frames B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X PTCCH Position of PTCCH on 52-Multiframe PTCCH is is a new logical channel in in 19 General Packet Radio Services

20 Radio Interface GSM Timing Advance and Guard Period timeslot n timeslot n+1 Power Ramping Burst in timeslot n Burst in timeslot n+1 Guard Period 8,25 bit periods 20 General Packet Radio Services

21 Radio Interface GSM Timing Advance and Guard Period BTS sends Timing Advance value to each MS individually to eliminate delay time effects BTS MS starts transmitting Timing Advance - bit periods earlier to be at the BTS side right in time MS 21 General Packet Radio Services

22 Radio Interface Packet Timing Advance Control Channel, PTCCH MS sends Access Burst on uplink Network sends Control Message on downlink = 1 Access Burst PTCCH / Uplink = 1 Radio Block = 4 Normal Bursts PTCCH / Downlink 22 General Packet Radio Services

23 Radio Interface Timing Advance on PTCCH = 1 Access Burst PTCCH / Uplink = 1 Radio Block = 4 Normal Bursts PTCCH / Downlink MS has 2 possibilities within 52 Multiframe, but network needs 4 Normal Burst to transmit the message! 52 Frames B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X PTCCH 23 General Packet Radio Services

24 Radio Interface 52-multiframe number n: Operation of PTCCH on 52 Multiframe uplink TAI=0 TAI=1 B0 B1 B2 0 B3 B4 B5 1 B6 B7 B8 2 B9 B10 B11 3 downlink TA_message 1 TA message 1 52-multiframe number n + 1: uplink TAI=2 TAI=3 B0 B1 B2 4 B3 B4 B5 5 B6 B7 B8 6 B9 B10 B11 7 downlink TA message 1 TA message 1 52-multiframe number n + 2: uplink TAI=4 TAI=5 B0 B1 B2 8 B3 B4 B5 9 B6 B7 B8 10 B9 B10 B11 11 downlink TA message 2 TA message 2 52-multiframe number n + 3: uplink TAI=6 TAI=7 B0 B1 B2 12 B3 B4 B5 13 B6 B7 B8 14 B9 B10 B11 15 downlink TA message 2 TA message 2 52-multiframe number n + 4: uplink TAI=8 TAI=9 B0 B1 B2 16 B3 B4 B5 17 B6 B7 B8 18 B9 B10 B11 19 downlink TA message 3 TA message 3 52-multiframe number n + 5: uplink TAI=10 TAI=11 B0 B1 B2 20 B3 B4 B5 21 B6 B7 B8 22 B9 B10 B11 23 downlink TA message 3 TA message 3 Combining 8 times the 52 Multiframe to get a PTCCH-Multiframe multiframe number n + 6: uplink TAI=12 TAI=13 B0 B1 B2 24 B3 B4 B5 25 B6 B7 B8 26 B9 B10 B11 27 downlink TA message 4 TA message 4 General Packet Radio Services

25 Radio Interface 52-multiframe number n: Operation of PTCCH on 52 Multiframe uplink TAI=0 TAI=1 B0 B1 B2 0 B3 B4 B5 1 B6 B7 B8 2 B9 B10 B11 3 downlink TA_message 1 TA message 1 52-multiframe number n + 1: uplink TAI=2 TAI=3 B0 B1 B2 4 B3 B4 B5 5 B6 B7 B8 6 B9 B10 B11 7 downlink TA message 1 TA message 1 52-multiframe number n + 2: uplink TAI=4 TAI=5 B0 B1 B2 8 B3 B4 B5 9 B6 B7 B8 10 B9 B10 B11 11 downlink TA message 2 TA message 2 52-multiframe number n + 3: uplink TAI=6 TAI=7 B0 B1 B2 12 B3 B4 B5 13 B6 B7 B8 14 B9 B10 B11 15 downlink TA message 2 TA message 2 52-multiframe number n + 4: uplink TAI=8 TAI=9 B0 B1 B2 16 B3 B4 B5 17 B6 B7 B8 18 B9 B10 B11 19 downlink TA message 3 TA message 3 52-multiframe number n + 5: TAI = Timing Advance Identifier to define the Frame, where the MS is allowed to transmit one Access Burst on the PTCCH/uplink uplink TAI=10 TAI=11 B0 B1 B2 20 B3 B4 B5 21 B6 B7 B8 22 B9 B10 B11 23 downlink TA message 3 TA message multiframe number n + 6: uplink TAI=12 TAI=13 B0 B1 B2 24 B3 B4 B5 25 B6 B7 B8 26 B9 B10 B11 27 downlink TA message 4 TA message 4 General Packet Radio Services

26 Radio Interface 52-multiframe number n: Operation of PTCCH on 52 Multiframe uplink TAI=0 TAI=1 B0 B1 B2 0 B3 B4 B5 1 B6 B7 B8 2 B9 B10 B11 3 downlink TA_message 1 TA message 1 52-multiframe number n + 1: uplink TAI=2 TAI=3 B0 B1 B2 4 B3 B4 B5 5 B6 B7 B8 6 B9 B10 B11 7 downlink TA message 1 TA message 1 52-multiframe number n + 2: uplink TAI=4 TAI=5 B0 B1 B2 8 B3 B4 B5 9 B6 B7 B8 10 B9 B10 B11 11 downlink TA message 2 TA message 2 52-multiframe number n + 3: uplink TAI=6 TAI=7 Network transmits Timing Advance Control Message with length of 4 Normal Burs ts on PTCCH/Downlink B0 B1 B2 12 B3 B4 B5 13 B6 B7 B8 14 B9 B10 B11 15 downlink TA message 2 TA message 2 52-multiframe number n + 4: uplink TAI=8 TAI=9 B0 B1 B2 16 B3 B4 B5 17 B6 B7 B8 18 B9 B10 B11 19 downlink TA message 3 TA message 3 52-multiframe number n + 5: uplink TAI=10 TAI=11 B0 B1 B2 20 B3 B4 B5 21 B6 B7 B8 22 B9 B10 B11 23 downlink TA message 3 TA message multiframe number n + 6: uplink TAI=12 TAI=13 B0 B1 B2 24 B3 B4 B5 25 B6 B7 B8 26 B9 B10 B11 27 downlink TA message 4 TA message 4 General Packet Radio Services

27 s can be done belonging 3 different modes. Fixed and dynamic allocation is mandatory, extended dynamic allocation is optional. fixed physical resource dynamic Extended dynamic 27 General Packet Radio Services

28 Dynamic Assignment Monitoring USF in Block B(n) Sends in Block B(n+1) or in Blocks B(n+1) - B(n+4) USF = R2 USF USF = R1 Radio Block B(n) downlink USF = Uplink State Flag USF = R3 USF =R4 uplink Radio Block B(n+1) USF sent in downlink Radio Block points to the user of the next uplink Radio Block (or the next 4 Radio Blocks, if USF Granularity bit is set) 28 General Packet Radio Services

29 Extended Dynamic Allocation Monitoring USF in Block B(n) Sends in Block B(n+1) or in Blocks B(n+1) - B(n+4) USF = R2 USF USF = R1 Radio Block B(n) downlink USF = Uplink State Flag USF = R3 uplink Radio Block B(n+1) USF =R4 USF allowing to transmit 1 or 4 Radio Blocks on that PDCH and on all higher numbered assigned PDCH s 29 General Packet Radio Services

30 Fixed Assignment Timeslot Allocation Allocation Bitmap example TN4 TN6 TN7 Bitmap example TDMA Frames Assigned Timeslots PDCH B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X B0 - B11 = Radio Blocks T = Frame used for PTCCH X = Idle frame = not assigned Radio Block = assigned Radio Block 30 General Packet Radio Services

31 Fixed Assignment Timeslot Allocation Allocation Bitmap example TN4 TN6 TN7 Bitmap example TDMA Frames 1. Element of fixed assignment: Timeslot Allocation Assigned Timeslots PDCH B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X Vector with 8 elements which assigns the timeslots that may be used by the MS for the data transfer B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X B0 - B11 = Radio Blocks T = Frame used for PTCCH X = Idle frame = not assigned Radio Block = assigned Radio Block 31 General Packet Radio Services

32 Fixed Assignment Timeslot Allocation Allocation Bitmap example TN4 TN6 TN7 Bitmap example TDMA Frames Assigned Timeslots 2. Element of fixed assignment: Allocation Bitmap PDCH Matrix with Nx12 elements: 12 lines, corresponding to the 12 Radio Blocks within the 52 Multiframe. N columns, depending on the N assigned timeslots with the Timeslot Allocation Vector B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X B0 B1 B2 T B3 B4 B5 X B6 B7 B8 T B9 B10 B11 X B0 - B11 = Radio Blocks T = Frame used for PTCCH X = Idle frame = not assigned Radio Block = assigned Radio Block 32 General Packet Radio Services

33 Packet Data Transfer Mobile Originated Packet Transfer 1 2 MS Packet Channel Request Packet Immediate Assignment Network PRACH or RACH PAGCH or AGCH Phase One Phase One Access Access 3 Packet Resource Request PACCH Phase Two Phase Access Two Access 4 Packet Resource Assignment PACCH (optional) 33 General Packet Radio Services

34 Packet Data Transfer Mobile originated data transfer: channel request Channel request via RACH or One phase access request Single block establishment Packet Channel request via PRACH One phase access request Short access request Two phase access request 34 General Packet Radio Services

35 Packet Data Transfer Network originated data transfer Common Control Channels or Circuit switched paging Packet switched paging Common Control Channels Circuit switched paging Packet Common Control Channels Packet switched paging 35 General Packet Radio Services

36 Thank you for your attention??? Further questions: or 36 General Packet Radio Services