01 - BreezeMAX - BWA concepts -(ver. 07-06-10) - ver. 2.0

8/6/2019 01 - BreezeMAX - BWA concepts -(ver. 07-06-10) - ver. 2.0

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Access SystemsAccess Systems11


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Overall Diagram

The System is designed to transfer information from its point ofgeneration (the user) to the first node of the (transport) network.

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Network Access Systemuser

user

user

user

user

user

Transport

Network


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Point to Multipoint Architecture2

WAN

(Internet / Intranet)

NetworkAccessSystem

NetworkAccessSystem

userLAN

user

user

user

userLAN

user

long(er) distances short distances

high capacity medium capacityQoS mandatory QoS not mandatory

licensed frequency bands(unlicensed also applicable)

unlicensed frequency bands

scheduled access contention based access

IEEE 802.16 IEEE 802.11


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Overall Diagram3

Indoor

Indoor

PSTN

Internet

Gateway

(GW)

Gatekeeper

(GK)

Router

(R)

servers

SNMP

mgr

Indoor

PCPC

Hub / Switch / Router

VoIPGateway

PC

PCPC

WirelessVoIP

Gateway

PC

Wireless


Wired / Wireless

Wired / Wireless

Indoor

PCPC

VoIPGateway

PC

Wireless


Wired / Wireless

100/1000MbpsEthe

rnetswitch


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BWA Concepts (IEEE 802.16)

Traffic is generated as Service Flows (SF)

Service Flow is a flow of packets to which specific QoS level is guaranteedService Flows and their associated QoS parameters are defined before the operation of thenetwork, but can also be modified, added or deleted during operation

Packets are identified as belonging to a specific Service Flow based on the Connection Identifier(CID)

CID is used by Subscriber Stations (SS) to request uplink bandwidth grants from the Base

Station (BS)

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WAN

(Internet / Intranet)userLAN

user

user

user

userLAN

user

BaseStation

(BS)

SubscriberStation

(SS)


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Four different types of bandwidth grants are defined:

Continuous Grant (CG)

For real time services like E1, VOIP (without silence suppression)

Fixed size data packets on a periodic basis

Service parameters: unsolicited grant size, normal grant interval

Real Time Variable Rate (RT-VR)

For real time services like MPEG video

Variable bit rates

Guaranteed rate and delay requirement

Service parameters: committed burst (CIR), polling time interval (CT)Non Real Time Variable Rate (NRT-VR)

Variable bit rate services

Guaranteed rate required, guaranteed delay not required

Service may expand to occupy full bandwidth rate limit required

Service parameters: committed burst, polling time interval, excess burst (MIR)Best Effort (BE)

For service with no rate or delay requirements

Service parameters: polling time interval, excess burst

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BWA Concept (BreezeMax)

Committed Time (CT)

The AU polls each SU about the BW they are required, the time interval between two polls isthe CT (divided by two)

CT is the time period where the configured BW (CIR or MIR) is measured

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Long Medium Short

CG* > 60 msec 40 - 60 msec 20 - 40 msec

RT 200 msec 100 msec 50 msec

NRT 200 msec 100 msec 50 msec

BE 200 msec 100 msec 50 msec

* Defined automatically when the grant interval is configured.


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Actual bandwidth grants to CIDs is executed by BS through the allocation of time slots fortransmission to the selected CIDs

Network time is divided into frames (of several ms)

Every downlink frame opens with a DL map followed by a UL map transmitted by BS to all SS

The maps indicate the activity to be executed by BS and SS during the frame

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DL BurstsUCDDCDUL MAPDL MAPPreamble

X msec (5 msec in BreezeMAX)

UL Bursts


UL Bursts

Half duplex operation

Full duplex operation

DL UL

DL

UL


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DL MAP indicates:

CIDs to which BS will transmit (downlink) during the following frame

The exact moment in time when the transmission will occur

UL MAP indicates:CIDs that have to transmit (uplink) during the next frame

The exact moment in time when the transmission has to occur

The type of information to be transmitted during the allocated interval (data, management,requests to transmit in the next frame, etc.)

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DL


DL





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DCD (Downlink Channel Descriptor) indicates:

The physical parameters to be used by BS for each CID (modulation type, FEC codingrate, etc.)

UCD (Uplink Channel Descriptor) indicates:

The physical parameters to be used by each CID when transmitting to BS(modulation type, FEC coding rate, etc.)

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DL


DL





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IEEE 802.16 Structure10

Common MAC

MAC

PHY

Common MAC, Several PHYs

2-11 GHzOFDMA PHY

2-11 GHzOFDM PHY

2-11 GHzSCa PHY

11-66 GHzSC PHY

OFDM Specific MACFeatures


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Frame Format11

MAC PDU

MAC Payload

EC0

Header

Type

LENCIRsv EKS Rsv

LEN - Cont.

CID

CID - Cont.

HCS

CRC

Format ofthe message

Length

Connection ID

Data / Management


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Frame Format12

MAC PDU

EC

Header

Type

BRCIRsv EKS Rsv

BR- Cont.

CID

CID - Cont.

Amount of datarequested to Tx

Connection ID

Bandwidth Request

1

Format ofthe message


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13 Typical Application


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01 - BreezeMAX - BWA concepts -(ver. 07-06-10) - ver. 2.0