OMF000001 Um interface and radio channels ISSUE1.4

Radio Access TechnologyTime FDMA Frequency TDMA Time Frequency CDMA Frequency Time Code... 8bit 41 synchronous bits 36 encrypted bits 3bit 68.25bitTail bit Data Tail bit Guard interval

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OMF000001 Um interface and

radio channels ISSUE1.4

OMF000001 Um interface and

radio channels ISSUE1.4

Wireless Training Department

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Overview

Processing of voice signal Radio channel

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A interface

MAP interface BTS

MSC

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Communication management (CM)

Radio resources management (RR)

Mobility and security management

Data link layer (L2)

Network application layer (L3)

Hierarchical Structure of Um Interface

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Radio Access Technology

Time

FDMA

Frequency

TDMA Time

Frequency

CDMA

Frequency Time

Code

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Radio Access Technology

Time

FDMA

Frequency

TDMA Time

Frequency

CDMA

Frequency Time

Code

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Overview

Processing of voice signal

Radio channel

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Voice A/D 8KHz ， 13bit Speech

coding

Speech coding

Segme ntation

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Speech Coding

Prediction (RPE-LTP) It works as follow: 8KHZ of sampling is performed first, then divided into frames with 20ms; every frame has 4 sub-frames; the duration of every sub-frame is 5ms; and the pure bit rate is 13kbit/s.

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Block coder

Excited coder

Excited coder 50bit

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1 2 3 4 5 6 7 8 452 453 454 455 456

B

8 16 456

2 10 450

6 14 454

1 9 449

4 12 452

7 15 455

3 11 451

5 13 453

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8 16 456

2 10 450

6 14 454

1 9 449

4 12 452

7 15 455

3 11 451

5 13 453

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3 57 1 26 1 57 3

Voice Burst

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Timing Advance (TA)

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Frequency HoppingFrequency

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Frequency HoppingFrequency

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Prolong battery life and reduce interference

DTX

 Shut off the transmission at voice intervals;

 Only transmit SID frames’

 The transcoder at the RX terminal produces comfortable noise.

 Implemented by the transcoder.

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 Shut off the transmission at voice intervals;

 Only transmit SID frames’

 The transcoder at the RX terminal produces comfortable noise.

 Implemented by the transcoder.

Prolong battery life and reduce interference

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Power Control

BCCH Carrier is not involved in

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Overview Processing process of voice channel

Radio channel

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58 information bits 26 training sequences 58 information bits

Constant bit 142Information bit 39 Extended training sequence 64Information bit 39

Normal burst (NB)

Frequency correction burst (FB)

Synchronous burst (SB)

1 hyper frame=2048 super-frames=2715648TDMA frames (3 hours, 28 minutes, 53 seconds and 760 milliseconds)

1 super-frame=1326TDMA frames (6.12 seconds)

1 multiframe=26TDMA frames (120ms) 1 multiframe=51TDMA frames (3060/13ms)

1TDMA frame=8 timeslots (120/26=4.615ms)

1 timeslot=156.25 bit duration (15/26=0.577ms)(1 bit duration: 48/13=3.68us)

BCCHCCCHSDCCH

TCHSACCH/TFACCH

Frame

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58 information bits 26 training sequences 58 information bits

Constant bit 142Information bit 39 Extended training sequence 64Information bit 39

Normal burst (NB)

Frequency correction burst (FB)

Synchronous burst (SB)

1 hyper frame=2048 super-frames=2715648TDMA frames (3 hours, 28 minutes, 53 seconds and 760 milliseconds)

1 super-frame=1326TDMA frames (6.12 seconds)

1 multiframe=26TDMA frames (120ms) 1 multiframe=51TDMA frames (3060/13ms)

1TDMA frame=8 timeslots (120/26=4.615ms)

1 timeslot=156.25 bit duration (15/26=0.577ms)(1 bit duration: 48/13=3.68us)

BCCHCCCHSDCCH

TCHSACCH/TFACCH

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8bit 41 synchronous bits 36 encrypted bits 3bit 68.25bit

Tail bit Data Tail bit Guard interval

• Access burst (AB): Used in MS initial access

Guard interval

• Frequency correction burst (FB): Used in frequency synchronization

between MS and BTS

bits

39 encrypted bits 3bit 8.25bit

Tail bit Data Data Tail bit Guard interval

64 synchronous bits

• Synchronous burst (SB): Used in timing synchronization between MS

and BTS

Burst

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3bit 142 modulation bits 3bit 8.25bit

• Dummy burst (DB): Used in transmission of filling frames by

BTS at timeslots when there is no information delivered

Burst

Tail bit Data Data Tail bit Guard interval

26bit

Training sequence

Frame stealing flag

• Normal burst (NB): Used to carry the information of the traffic channel and

the control channel except for RACH

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Broadcast control channel

Common control channel

(CCCH)

Voice channel (TCH)

Common channel (CCH)

Dedicated channel (DCH) Logical channel

Logical Channel Type

ry

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FCCH SCH BCCH PCH AGCH

BCCH

CCCH

Common Channel

SDCCH SACCH FACCH TCH/F TCH/H

DCCH

TCH

Dedicated Channel

Downlink Logical Channel

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Downlink Logical Channel

FCCH SCH BCCH PCH AGCH

BCCH

CCCH

Common Channel

DCCH

TCH

Dedicated Channel

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RACH CCCH

Common channel

DCCH

TCH

Dedicated channelUplink Logical Channel

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Uplink Logical Channel

Common channel

DCCH

TCH

Dedicated channel

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Use of Logical Channels

Search for frequency correction burst

Search for synchronization sequence

Read system information

Listen paging message

Send access burst

Wait for signaling channel allocation

PCH RACH AGCH

SDCCH SDCCH TCH FACCH

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BCCH+CCCH (extended BCCH)

SDCCH/8+SACCH/C8 (main SDCCH)

Physical Combination of Logical Channel

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Structure of Logical Channel Combination

Frame-Main BCCH

1 multi-frame (51TDMA Frames) 235.38ms Downlink

Group3,4 (same as Group2)

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12-

16-19 20 21

25

22-

26-29 30 31

35

32-

36-39 40 41

45

42-

46-49 50

1 multi-frame (51TDMA Frames) 235.38ms Uplink Channel D3×4 R R A2×4 A3×4 R……R D0×4 D1×4 R R D2×4 Channel D0×4 R R A0×4 A1×4 R……R D0×4 D1×4 R R D2×4 Frame

Number 0-3 4 5 6-9 10-13 14-36 37-40 41-44 45 46 47-50

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PCH AGCH RACH

How to determine the total CCCH resources of the cell? How to

allocate AGCH and PCH reasonably?

Configuration of Common Control Channel

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CCCH Grouping

combinations (GPRS not taken into account), in which the main BCCH, extended BCCH, combined BCCH, and the BCCH+CBCH combination contain the CCCH, i.e all of the four combinations support the MS access The MS are distributed to different CCCH groups based on this fact.

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CCCH Grouping

0, 2, 4 and 6 but the extended BCCH combination can only be mapped to timeslots 2, 4 and 6 because it does not contain FCCH and SCH Therefore, all MS synchronize with the base station at timeslot 0 and access the network via different CCCH.

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Paging Group

groups the MS can be divided into 81 sub-groups at most from the opinion of the paging group No matter what combination mode is adopted, the number of blocks used for paging in every 51 multi-frame does not exceed 9 The system enables the 51 multi-frame to cycle again , with a quantity of

“BS-PA-MFRAMS” (number of frames of the same paging) of

51 multi-frames as a period.

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Paging Group

a paging group Therefore, the number of paging frames in the system is the “number of frames of the same paging” The number of paging groups in each super-group is

super-9 or 3 – “number of access granted reserved blocks”.

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Calculation of CCCH and Paging Group

CHANS x N)] div N

CHANS x N)] mod N

In the formula:

N = Number of paging groups x BS-PA-MFRAMS

IMSI = IMSI number of the mobile phone

mod = Modulo calculation

div = Divide exactly

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discontinuous transmission (DTX)?

there?

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