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IEEE Std 802.16-2001

LOCAL AND METROPOLITAN AREA NETWORKS—PART 16:

8.2.5.4.10 Summary of downlink PHY parameters

The downlink PHY parameters are summarized in Table 104.

Table 104—Summary of downlink PHY Parameters

Transmission convergence sublayer

Includes 1 pointer byte

 

 

 

Reed-Solomon over GF(256)

 

Information byte lengths: 6–255 bytes

Outer Coding

Error correction capability R = 0-32 (T=0-16)

 

BTC (optional)

 

NOTE—There is no inner code selected in this case.

 

 

Randomization

1 + X14 + X15

Initialization: 100101010000000 at the beginning of each burst

 

 

 

 

Selectable from the following options:

Inner Coding

None

(24,16) block convolutional code

 

 

(9,8) parity check code (optional)

 

 

Preamble

Frame Start Preamble (32 symbols)

Downlink TDMA Burst Preamble (16 symbols)

 

 

 

Modulation

QPSK (mandatory), 16-QAM (mandatory), 64-QAM (optional)

 

 

Spectral shaping

α=0.25

 

 

8.2.6 Uplink physical layer

8.2.6.1 Uplink subframe

The structure of the uplink subframe used by the SS to transmit to the BS is shown in Figure 123. Three classes of bursts may be transmitted by the SS during the uplink subframe:

a)Those that are transmitted in contention opportunies reserved for Initial Maintenance.

b)Those that are transmitted in contention opportunies defined by Request Intervals reserved for response to multicast and broadcast polls.

c)Those that are transmitted in intervals defined by Data Grant IEs specifically allocated to individual SSs.

Any of these burst classes may be present in any given frame. They may occur in any order and any quantity (limited by the number of available PSs) within the frame, at the discretion of the BS uplink scheduler as indicated by the UL_MAP in the frame control section (part of the downlink subframe).

The bandwidth allocated for Initial Maintenance and Request contention opportunies may be grouped together and is always used with the uplink burst profiles specified for Initial Maintenance Intervals (UIUC=2) and Request Intervals (UIUC=1), respectively. The remaining transmission slots are grouped by SS. During its scheduled bandwidth, an SS transmits with the burst profile specified by the BS.

SS Transition Gaps separate the transmissions of the various SSs during the uplink subframe. The gap allows for ramping down of the previous burst, followed by a preamble allowing the BS to synchronize to the new SS. The preamble and gap lengths are broadcast periodically in the UCD message.

246

Copyright © 2002 IEEE. All rights reserved.

AIR INTERFACE FOR FIXED BROADBAND WIRELESS ACCESS SYSTEMS IEEE Std 802.16-2001

 

 

 

SS Transition

 

Tx/Rx Transition

 

 

 

Gap

 

Gap (TDD)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Initial

Request

 

SS 1

 

 

 

 

SS N

 

Maintenance

Contention

 

Scheduled

 

 

 

 

Scheduled

 

Opportunities

Opps

 

Data

 

 

 

 

Data

 

(UIUC=2)

(UIUC=1)

 

(UIUC=i)

 

 

 

 

(UIUC=j)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Access

 

Collision

Access

Bandwidth

Collision

Bandwidth

 

Burst

 

 

 

 

Burst

Request

 

 

 

Request

Figure 123—Uplink subframe structure

8.2.6.1.1 Uplink burst preamble

Each uplink burst shall begin with an uplink preamble. This preamble is based upon a repetition of a +45 degrees rotated constant amplitude zero auto-correlation (CAZAC) sequence (Milewski [B15]). The preamble length is either 16 symbols or 32 symbols. In the 16-symbol preamble (whose sequence is specified in Table 105), the CAZAC sequence is of length 8 and repeated once. In the 32-symbol preamble (whose sequence is specified in Table 106), the CAZAC sequence is of length 16 and repeated once.

Table 105—16-symbol uplink preamble sequence

Symbol

 

I

 

Q

 

B(1)

B(2)

 

 

 

 

 

 

 

 

1 and 9

1

 

1

 

0

 

0

 

 

 

 

 

 

 

 

2 and 10

–1

 

1

 

1

 

0

 

 

 

 

 

 

 

 

3 and 11

1

 

1

 

0

 

0

 

 

 

 

 

 

 

 

4 and 12

1

 

1

 

0

 

0

 

 

 

 

 

 

 

 

5 and 13

–1

 

–1

 

1

 

1

 

 

 

 

 

 

 

 

6 and 14

–1

 

1

 

1

 

0

 

 

 

 

 

 

 

 

7 and 15

–1

 

–1

 

1

 

1

 

 

 

 

 

 

 

 

8 and 16

1

 

1

 

0

 

0

 

 

 

 

 

 

 

 

Copyright © 2002 IEEE. All rights reserved.

247

IEEE Std 802.16-2001

LOCAL AND METROPOLITAN AREA NETWORKS—PART 16:

Table 106—32-symbol uplink preamble sequence

Symbol

I

Q

B(1)

B(2)

 

 

 

 

 

1 and 17

1

1

0

0

 

 

 

 

 

2 and 18

1

1

0

0

 

 

 

 

 

3 and 19

1

–1

0

1

 

 

 

 

 

4 and 20

–1

–1

1

1

 

 

 

 

 

5 and 21

–1

–1

1

1

 

 

 

 

 

6 and 22

1

1

0

0

 

 

 

 

 

7 and 23

1

1

0

0

 

 

 

 

 

8 and 24

–1

1

1

0

 

 

 

 

 

9 and 25

1

1

0

0

 

 

 

 

 

10 and 26

1

1

0

0

 

 

 

 

 

11 and 27

–1

1

1

0

 

 

 

 

 

12 and 28

1

1

0

0

 

 

 

 

 

13 and 29

–1

–1

1

1

 

 

 

 

 

14 and 30

1

1

0

0

 

 

 

 

 

15 and 31

–1

–1

1

1

 

 

 

 

 

16 and 32

1

–1

0

1

 

 

 

 

 

The amplitude of the preamble shall depend on the uplink power adjustment rule (8.2.6.3.7). In the case of the constant peak power scheme (power adjustment rule=0), the preamble shall be transmitted such that its constellation points coincide with the outermost constellation points of the modulation scheme in use. In the case of the constant mean power scheme (power adjustment rule=1), it shall be transmitted with the mean power of the constellation points of the modulation scheme in use.

The BS defines the preamble length through the UCD message.

8.2.6.1.2 UL_MAP_Information_Element definition

The format of UL_MAP_Information_Elements shall be as defined in Table 107 and utilized according to 6.2.2.3.4. The Uplink Interval Usage Code shall be one of the values defined in Table 108. The Offset indicates the start time, in units of minislots, of the burst relative to the Allocation Start Time given in the UL-MAP message. The end of the last allocated burst is indicated by allocating a NULL burst (CID = 0 and UIUC = 10) with zero duration. The time instants indicated by the offsets are the transmission times of the first symbol of the burst, including the preamble.

248

Copyright © 2002 IEEE. All rights reserved.

AIR INTERFACE FOR FIXED BROADBAND WIRELESS ACCESS SYSTEMS

IEEE Std 802.16-2001

Table 107—UL_MAP_Information_Element

 

 

 

 

Syntax

 

Size

 

Notes

 

 

 

 

 

 

 

 

 

 

 

UL_MAP_Information_Element() {

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CID

 

 

16 bits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UIUC

 

 

4 bits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Offset

 

 

12 bits

 

offset, in units of mini-slots,

 

 

 

 

 

 

 

 

 

of the preamble relative to

 

 

 

 

 

 

 

 

 

the Allocation Start Time

 

 

 

 

 

 

 

 

 

 

 

 

}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 108—Uplink map IE

 

 

 

 

 

 

 

 

 

 

 

 

IE name

 

UIUC

Connection

 

 

 

Description

 

ID

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

reserved

 

0

NA

Reserved for future use.

 

 

 

 

 

 

 

Request

 

1

any

Starting offset of request region.

 

 

 

 

 

Initial

 

2

broadcast

Starting offset of maintenance region (used in Initial Ranging).

Maintenance

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Station

 

3

unicast

Starting offset of maintenance region (used in Periodic Ranging).

Maintenance

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Grant

 

4

unicast

Starting offset of Data Grant Burst Type 1 assignment.

Burst Type 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Grant

 

5

unicast

Starting offset of Data Grant Burst Type 2 assignment.

Burst Type 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Grant

 

6

unicast

Starting offset of Data Grant Burst Type 3 assignment.

Burst Type 3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Grant

 

7

unicast

Starting offset of Data Grant Burst Type 4 assignment.

Burst Type 4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Grant

 

8

unicast

Starting offset of Data Grant Burst Type 5 assignment.

Burst Type 5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Grant

 

9

unicast

Starting offset of Data Grant Burst Type 6 assignment.

Burst Type 6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Null IE

 

10

zero

Ending offset of the previous grant.

 

 

 

Used to bound the length of the last actual interval allocation.

 

 

 

 

 

 

 

 

 

 

Empty

 

11

zero

Used to schedule gaps in transmission.

 

 

 

 

 

 

 

reserved

 

12-15

N/A

Reserved.

 

 

 

 

 

 

 

 

 

 

 

 

Copyright © 2002 IEEE. All rights reserved.

249

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