November 2005 doc IEEE 802 22 05 0092r0 Nextwave Broadband WRAN Proposal by tomato739

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									November 2005                                                                                                             doc.: IEEE 802.22-05/0092r0


           Nextwave Broadband WRAN Proposal
                         IEEE P802.22 Wireless RANs                                                                      Date: 2005-11-07
Authors:
 Name                           Company                             Address                                      Phone                    email
 Ramon Khalona                  Nextwave Broadband                  2075 Las Palmas Drive                        760-710-2063             rkhalona@nextwavetel.com
                                                                    Carlsbad, CA 92009 U.S.A.




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Submission                                                                                  Slide 1                             Ramon Khalona/Nextwave Broadband, Inc.
November 2005                          doc.: IEEE 802.22-05/0092r0


                         Abstract

      Nextwave Broadband intends to submit a WRAN
      proposal that
 •    Is based on 802.16e OFDMA PHY/MAC (5MHz
      profile)
 •    Is compliant with the 802.22 FRD document
 •    Addresses coexistence concerns with incumbent
      services
 •    Incorporates additional features to achieve maximum
      spectral efficiency and coverage


Submission                   Slide 2     Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                           doc.: IEEE 802.22-05/0092r0

                      802.22 Protocol Reference Model


                   Scope of Standard


                             CS SAP

                      Convergence Sublayer                 Management Entity
                              (CS)                        Convergence Sublayer




                                                                                               Network Management System
                            MAC SAP
             MAC




                   MAC Common Part Sublayer                Management Entity
                         (MAC CPS)                      MAC Common Part Sublayer



                        Security Sublayer                   Security Sublayer
                           PHY SAP
             PHY




                         Physucak Layer
                             (PHY)                         Management Entity
                                                              PHY Layer

                    Data/Control Plane                    Management Plane




Submission                                    Slide 3      Ramon Khalona/Nextwave Broadband, Inc.
November 2005                           doc.: IEEE 802.22-05/0092r0

                 PHY/MAC Summary
 • The proposed PHY/MAC
       = a subset of 802.16 PHY/MAC + enhancements required
 • The subset of 802.16 PHY/MAC
       = the subnet that supports the S-OFDMA PHY/MAC, as
         specified in the following references:
          • IEEE Std 802.16-2004
          • IEEE P802.16-2004/Cor1/D5
          • IEEE P802.16e/D12




Submission                    Slide 4     Ramon Khalona/Nextwave Broadband, Inc.
November 2005                               doc.: IEEE 802.22-05/0092r0

                       PHY Summary
             (based on 802.16e OFDMA 5 MHz Profile)
 Channel Bandwidth                 5 MHz
 Modulation                       QPSK/16-QAM/64-QAM
 Coding                           Conv./Conv. Turbo
                                  (r = 1/2, 2/3, 3/4)
 Duplex Method                    TDD
 FFT Size                         512
 OFDMA Symbol Time                100.8 µs (11.2 µs guard)
 Frame size(s)                    5 ms, 10 ms
                                  (49, 98 OFDM symbols, respectively)
 Diversity Scheme                 Space Time Coding (STC)
                                  + Beamforming
                                  (for enhanced coverage and range)
Submission                    Slide 5         Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                         doc.: IEEE 802.22-05/0092r0


                 PHY Summary (Cont.)
                                                                                                        Time
                                                 MAC             MAC          MAC        MAC frame      …….
                                               Frame n-1       frame n     frame n+1       n+2

                                                                    TDD MAC Frame
                                                                          TTG                     RTG
 TDD Frame structure with multiple
                                                           DL Subframe              UL Subframe
   zones in DL and UL subframes




Submission                           Slide 6                Ramon Khalona/Nextwave Broadband, Inc.
November 2005                          doc.: IEEE 802.22-05/0092r0
                 OFDMA Frame Structure
                (with only mandatory Zone)




Submission                 Slide 7       Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                         doc.: IEEE 802.22-05/0092r0

                      PHY Summary (Cont.)
              DL distributed subcarrier permutation
 BW = 5 MHz, NFFT = 512                        FUSC                      PUSC
 Number of Guard subcarriers                     86                          91
 Number of clusters/subchannels                  --                       30/15
 Number of used subcarriers                     426                         421
 Number of data subcarriers                     384                         360
 Number of pilot subcarriers                     42                          60
 Number of subchannels                           8                           15
 Subcarrier Permutation                        Type 1                   Type 1
                                            (802.16-2004)            (802.16-2004)
 Cluster renumbering                             --                     Activated




Submission                        Slide 8               Ramon Khalona/Nextwave Broadband, Inc.
November 2005                               doc.: IEEE 802.22-05/0092r0

                     PHY Summary (Cont.)
              UL distributed subcarrier permutation

 BW = 5 MHz, NFFT = 512                  PUSC                    OPUSC
 Number of guard subcarriers              103                         79
 Number of tiles                          102                        144
 Number of used subcarriers               409                        433
 Number of subchannels                    17                          24
 Tile permutation                        Type 2                       --
 Subcarrier permutation                  Type 3                    Type 4




Submission                     Slide 9          Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                                       doc.: IEEE 802.22-05/0092r0

                    PHY Summary (Cont.)
             DL/UL adjacent subcarrier permutation
                    BW = 5 MHz, NFFT = 512                Subcarriers
                    Number of Guard                           79
                    subcarriers
                    Number of used subcarriers                433
                    Number of data subcarriers                384
                    Number of pilot subcarriers                48
                    (Npilots)
                    Number of data subcarriers
                    Number of bands                            12

                    Number of bins per band                    4

                    Number of subcarriers per                  9
                    bin (8 data +1 pilot)

                    Number of subchannels                      8

                    Subcarrier Permutation                   None

                    Pilot subcarrier index         9k+3m+1,
                                                   for k=0,1,……, Npilots and
                                                   m=[symbol index] mod 3




Submission                                   Slide 10                   Ramon Khalona/Nextwave Broadband, Inc.
    November 2005                                   doc.: IEEE 802.22-05/0092r0


                     Proposed MAC -- Highlights
•     Designed for Broadband Wireless Access systems;
•     Topologies: Point-to-point, Point-to-Multipoint
•     Connection-oriented
•     Multiple Access: TDM, TDMA, and OFDMA
•     Duplex modes: TDD
•     Adaptive burst profiles (Modulation and FEC) on both DL and UL
•     Upper layer Protocol-independent core (ATM, IP, Ethernet, ……)
•     Flexible QoS offering (CBR, rt-VBR, nrt-VBR, BE, and ERT-VR)
•     Strong security support (Privacy Key management, Authorization, data
      encryption, message authentication)
•     Robust link layer error control: ARQ and HARQ
•     Flexible and efficient MAC PDU and MAC management message
      encodings
•     Procedures for Shared Frequency Band Usage

           Combined benefits from ATM + DOCSIS

    Submission                         Slide 11       Ramon Khalona/Nextwave Broadband, Inc.
    November 2005                                                    doc.: IEEE 802.22-05/0092r0

                          IEEE 802.16 MAC – Three SubLayers
•     Convergence Sublayer (CS)
        – Mapping upper-layer data into MAC SDUs
        – upper-layer data traffic classifications, i.e., mapping to proper connection.
        – Payload header suppression (PHS)
•     MAC Common Part Sublayer (MAC CPS)
        –   access control
        –   MAC PDU encoding and decoding
        –   Bandwidth management
        –   MAC connection management
        –   QoS provision
•     Security Sublayer
        – Functions:
                 • Secures over-the-air transmissions
                 • Protects from theft of service
        – component protocols:
                 •   Message authentication
                 •   Authorization policy
                 •   Data encryption protocol
                 •   A client/server model based Key management protocol (Privacy Key Management,
                     or PKM)


    Submission                                          Slide 12       Ramon Khalona/Nextwave Broadband, Inc.
    November 2005                                                     doc.: IEEE 802.22-05/0092r0


                       IEEE 802.16 MAC
                  – Access Control Mechanisms
•   Contention-Free Access
      – the major access mechanism;
      – used for all data transmissions and most of the control message transmissions;
      – BS centralized scheduling: use the DL-MAPs/and UL-MAPs to specify who, when,
        how, and how long to access the air link;
      – TDM, TDMA, and OFDMA.
•   Contention-based Access
      – the supporting access mechanism;
      – only used for some special control signaling, e.g., initial ranging, bandwidth request,
        etc.
      – Collision Detection and Resolution
           • Detection: SS does not get the expected response in a given time
           • Resolution: a truncated binary exponential backoff window




    Submission                                       Slide 13             Ramon Khalona/Nextwave Broadband, Inc.
  November 2005                                   doc.: IEEE 802.22-05/0092r0


                    802.16 MAC Connections
• 802.16MAC is connection-oriented!!
• 802.16 MAC Connection
   – Unidirectional;
   – 16-bit connection ID (i.e., CID), used in MAC PDU Header;
   – Unique CID on per direction basis;
   – Associated with Service flow to define QoS parameters;
   – Associated with Security association to define the security paramters;
   – Connection creation and termination are triggered by higher layers;
   – For each direction, two mandatory management connections:
      • Basic connection
      • Primary management connection
   – For each direction, one optional management connection:
      • Secondary management connection

  Submission                          Slide 14      Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                                                    doc.: IEEE 802.22-05/0092r0

                                     MAC PDU Format
                           msb                                                                                 lsb

                            Generic MAC
                                                                                                        CRC
    MAC PDU                   Header                     payload (optional)                           (optional)
                             (6 bytes)




    Generic MAC Header Format                                Signalling Header Format
    (Header Type (HT) = 0)                                   (Header Type (HT) =1)
                                 E              LEN
    H E
               Type (6 bits)     S
                                   C EKS rs
                                                msb          H E       Type             Header Content
    T C                            I (2) v                   T C      (3 bits)             msb (11)
                                 F               (3)

             LEN lsb (8)             CID msb (8)                  Header Content (8)          CID msb (8)


             CID lsb (8)              HCS (8)                        CID lsb (8)                HCS (8)




Submission                                             Slide 15                    Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                        doc.: IEEE 802.22-05/0092r0

                MAC Management Messages and
                  TLV Encoding Mechanism
•   MAC management message format:
                     8 bits

                    mgmt
                    msg        MAC mgmt msg payload
                     HD



• MAC management messages can only be sent on the management
  connections;
• MAC management messages have two type of information fields:
   • Fixed field
   • TLV: a triplet (type, length, value), e.g. in UCD message, the TLV for
         uplink center frequency is (5, 4, f), where f is the frequency in KHz, 5 is
         type, and 4 is the length of f in bytes.



Submission                              Slide 16        Ramon Khalona/Nextwave Broadband, Inc.
     November 2005                                          doc.: IEEE 802.22-05/0092r0
                               802.16 MAC QoS Supports
•   Three basic components:
     – Service flow QoS scheduling
     – Dynamic service establishment
     – Two-phase activation model (i.e., admit first, then activate)
•   QoS related concepts/mechanisms
     – QoS Parameters
     – Scheduling Services, i.e., Service Types:
          •   Unsolicited Grant Service (UGS),
          •   Real-time Variable Rate (rt-VR),
          •   Extended Real-time Variable Rate (Ert-VR),
          •   Non-real-time Variable Rate (nrt-VR), and
          •   Best Effort (BE).
     –   16MAC Connections / 16MAC Service Flows
     –   Traffic classification (in MAC Convergence sublayer)
     –   Bandwidth Allocation
     –   BS scheduler and SS scheduler (not standardized, i.e., out of scope of 802.16
         standard)


     Submission                                  Slide 17     Ramon Khalona/Nextwave Broadband, Inc.
    November 2005                         doc.: IEEE 802.22-05/0092r0

                    802.16 MAC QoS Parameters

•    Minimum Reserved Traffic Rate
•    Minimum Tolerable Traffic Rate
•    Maximum Sustained Traffic Rate
•    Maximum Traffic Burst
•    Max Latency
•    Tolerated Jitter
•    Traffic Priority
•    Request/Transmission Policy



    Submission                 Slide 18     Ramon Khalona/Nextwave Broadband, Inc.
    November 2005                                    doc.: IEEE 802.22-05/0092r0

                          Bandwidth Allocation

•   Bandwidth is allocated to SS/SS by the BS scheduler in the form of scheduled
    transmissions;
•   Each scheduled transmission is defined by:
     –   Who to Tx
     –   When to Tx
     –   How long to Tx
     –   How to Tx
•   Service flow QoS based scheduling/bandwidth allocation;
•   DL and UL bandwidth partition
     – FDD: determined by regulatory rules and network planning;
     – TDD: adaptive DL/UL bandwidth partition;
•   Different schemes to collect DL and UL bandwidth requirements.




    Submission                           Slide 19       Ramon Khalona/Nextwave Broadband, Inc.
    November 2005                                     doc.: IEEE 802.22-05/0092r0


                     UL Bandwidth Request

•   UL BW requests per connection tell the BS the SS/MS’s traffic composition;
•   Two types of BW requests:
     – Incremental: add the new req. to the perception of the BW needs;
     – Aggregate: replace its perception of the BW needs with the new requested
         quantity.
•   Self correcting for BW request, i.e.,
     – No acknowledgement for BW req.
     – All BW req. errors are handled by periodically using “aggregate” BW req.
•   UL Bandwidth Request Transmission:
     – Contention-free
     – Contention-based




    Submission                           Slide 20        Ramon Khalona/Nextwave Broadband, Inc.
  November 2005                             doc.: IEEE 802.22-05/0092r0



                   UL Bandwidth Grant

• BW grants are per Subscriber Station (GPSS):
   – Allows real-time reaction to QoS need, i.e., SS may re-distribute
     bandwidth among its connections, maintaining QoS and service-
     level agreements
   – Lower overhead, i.e., less UL-MAP IE entries compare to grant per
     connection;
   – off- loading base station’s work
   – requires intelligent subscriber station, i.e, SS/MS scheduler




  Submission                     Slide 21     Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                                      doc.: IEEE 802.22-05/0092r0

                         RF Link Management
•    Ranging
      – Ranging is a process of acquiring the correct timing offset, and PHY
        parameters, such as, Tx power level, frequency offset, etc. so that the SS can
        communicate with the BS correctly;
      – BS performs measurements and feedback;
      – SS performs necessary adjustments;
      – Two types of Ranging for Fixed Applications:
             • Initial ranging: for a new SS to join the system
             • Periodic ranging (also called maintenance ranging): dynamically maintain a good RF
               link;
•    DL burst profile management
      – SS monitors the DL RF link quality;
      – SS reports DL link quality measurements to the BS;
      – Either BS or SS can initiate the process of changing DL burst profile
        (modulation, coding, etc.) for the SS.




Submission                                        Slide 22            Ramon Khalona/Nextwave Broadband, Inc.
November 2005                       doc.: IEEE 802.22-05/0092r0


                  MAC ARQ

• MAC ARQ, i.e., part of the MAC layer;
• ARQ can be enabled / disabled on a per-connection
  basis by using DSA/DSC messages;
• A connection cannot have a mixture of ARQ and non-
  ARQ traffic;
• CRC-32 shall be used in all MAC PDUs on an ARQ-
  enabled connection.




Submission               Slide 23     Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                                    doc.: IEEE 802.22-05/0092r0


             IEEE 802.16 Hybrid ARQ (HARQ)
•   HARQ can be enabled and disabled on per connection basis
•   Two basic HARQ variants:
     – CC: Chase Combining
             • One version of the encoded HARQ packet
             • No SPID (subpacket ID)
     – IR: Incremental redundancy
             • Several versions of the encoded HARQ subpackets
             • Use SPID to identify each subpacket
• Per allocation (burst) usages
     – Cannot mix HARQ and non-HARQ traffic on the same burst, allocated by one
       MAP-IE
     – Can mix HARQ bursts and non-HARQ bursts in the same MAC frame




Submission                                     Slide 24            Ramon Khalona/Nextwave Broadband, Inc.
  November 2005                                    doc.: IEEE 802.22-05/0092r0
               Coexistence Procedures for Shared
                    Frequency Band Usage
• Purposes of the procedures:
    – Reduction of interference to/from other systems or services; and/or
    – Facilitate coexistence of systems; and/or
    – Compliant with the regulatory requirements.
• The defined Procedures include:
    – Testing channels for other users including specific spectrum users
    – Discontinuing operations after detecting other users including specific
      spectrum users
    – Detecting other users including specific spectrum users
    – Scheduling for channel testing
    – Requesting and reporting of measurements
    – Selecting and advertising a new channel



  Submission                          Slide 25       Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                     doc.: IEEE 802.22-05/0092r0


                   Performance Summary

 • Spectral Efficiency: up to 3 bps/Hz
      Achieved through the use of spatial and time diversity techniques
      (MIMO/H-ARQ)
 • Data rates: 15 Mbps (peak) in both directions (5 MHz)
      Achieved through the use of high order modulation in moderate-to-
      good channel conditions (w. diversity).
      Key goal of proposal will be to achieve graceful degradation towards
      cell edge
 • Range Extension through Beamforming and Repeaters
      Typical cell radii (in the order of < 10 Km) can be extended through
      the use of beamforming techniques and/or distributed repeater
      architecture

Submission                           Slide 26       Ramon Khalona/Nextwave Broadband, Inc.
November 2005                                                             doc.: IEEE 802.22-05/0092r0

     Performance Improvement with Diversity Techniques
      (802.16d/3GPP frequency selective channel model)




    Percentage of cell area with data rates less than         Maximum throughput of Space-Time Coding/Spatial
    1.5 Mbps                                                  Multiplexing techniques with precoding

       (A. Ghosh et al., “Broadband Wireless Access with WiMax/8O2.16: Current Performance Benchmarks and Future
                           Potential,” IEEE Communications Magazine, February 2005, pp. 129-136)


Submission                                              Slide 27             Ramon Khalona/Nextwave Broadband, Inc.

								
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