CONTENTS

 1 Introduction
2 Types of FWA systems conveying IP packets or ATM cells in terms of radio channel utilization
3 Scope
4 References
5 Abbreviations
6 Technical characteristics addressed
        6.1 Modulation and multiple access method
        6.2 CoS and QoS
        6.3 Transfer delay characteristics
                  6.3.1 Considerations on IPTD
                  6.3.2 Considerations on IPDV
        6.4 VoIP technique
        6.5 Efficient spectrum utilization technique
        6.6 Error correction techniques in an ATM-based FWA system
Annex 1 � Mechanism to ensure QoS or CoS  in the broadband FWA systems
1 Introduction
2 Overview of CoS control
        2.1 Airplane model
        2.2 CoS control mechanism for the best effort flows in the FWA environment
                  2.2.1 Priority control for the CoS control
                  2.2.2 Priority determination
                  2.2.3 Notification of the CoS to subscribers
        2.3 Effect of CoS control
                  2.3.1 Fair access
                  2.3.2 End-to-end CoS control
3 Queuing and priority management mechanisms to support CoS controls in the FWA systems
        3.1 Introduction
        3.2 Queuing mechanisms for FWA systems
                  3.2.1 First in First out (FIFO) queuing
                  3.2.2 Priority queuing
                  3.2.3 Class based queuing (CBQ)
                  3.2.4 Weighted fair queuing (WFQ)
        3.3 CoS control schemes on layer 3 or higher
                  3.3.1 Multi-protocol label switching (MPLS)
                  3.3.2 Differentiated services (DiffServ)
                  3.3.3 Policy-based network management for CoS provision
                  3.3.4 CoS control mechanism in the FWA systems
4 CoS control mechanism of FWA systems using a distributed control scheme
        4.1 Extension of CSMA/CA protocol to support CoS controls
        4.2 Original CSMA/CA protocol
        4.3 Modified CSMA/CA for service differentiation
        4.4 CoS control based on EDCF in an FWA system
                  4.4.1 Legacy DCF
                  4.4.2 Enhanced distributed coordination function (EDCF)
                  4.4.3 Backoff algorithm
                  4.4.4     Arbitration inter-frame space (AIFS)
        4.5 An example of CoS service class (IEEE 802.1D Annex H2)
5 A mechanism for FWA systems using a centralized control scheme
        5.1 Introduction
        5.2 An example of QoS class in a wireless system
        5.3 Calculation of effective bandwidth for different services
Conversational service
Streaming service
Interactive service
Background service
        5.4 Scheduling function for a bandwidth assignment in the base station
                  5.4.1 Dynamic slot assignment (DSA)
                  5.4.2 Bandwidth assignment control by scheduler
Step 1: Assignment of the reserved bandwidth
Step 2: Assignment of the control
Step 3: Assignment of broadcast (BC) and multicast (MC) bandwidth
Step 4: Assignment of the additional bandwidth of each connection
6 Comparison of QoS characteristics of FWA systems using a distributed control scheme and a centralized control scheme
Annex 2 � Example calculations of average access protocol delay and delay variation of CSMA/CA-based FWA
1 Introduction
2 Approximations
3 Examples of packet delay calculation in short packet flow situations
4 Examples of packet delay calculation in long packet flow situations
Annex 3 � Example calculations of additional waiting time in multiple VoIP flow situations for TDMA-based FWA
1 Uplink scheduling services
2 Unsolicited grant service (UGS)
3 Frame structure
4 Assumptions for calculation
5 Results of example calculations
Annex 4 � Example calculations of QoS Class 0 network delay
1 Delay calculation in access networks including FWA systems
2 Example calculations of QoS class 0 network delay in UNI-UNI
Annex 5 � Technical characteristics of broadband FWA systems to support VoIP technique
1 Introduction
2 Required parameters for VoIP in relation to the end-to-end performance objectives
3 Consideration to satisfy the performance parameters for VoIP conveyed in FWA systems
        3.1 Delay and echo
        3.2 Packet loss
4 Example of speech quality for hypothetical paths including FWA
        4.1 Coder delay
        4.2 Mouth-to-ear delay
        4.3 Example calculation of R-value
Annex 6 � Techniques to improve spectrum utilization efficiency
1 Introduction
2 Statistical multiplexing
3 Bit‑rate reduction over the radio channel
Annex 7 � Error correction techniques in an ATM-based FWA system
1 ARQ for an ATM-based FWA system
        1.1 Introduction
        1.2 Comparison on different ARQ approaches
        1.3 Methods to send error notifications from the receiver to the transmitter
        1.4 Avoidance of excessive repetition
2 Error correction in an ATM cell transmission
        2.1 General considerations
        2.2 HEC vs. FEC and effects of differential encoding
        2.3 Example of a method to avoid effects of differential coding when HEC without FEC is applied