1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0700716.2000(R2009) Air Interface Standard for Broadband Direct Sequence CDMA for Fixed Wireless PSTN Access Layer 1 ATIS is the leading technical planning and standards development organization committed to the rapid development of global, mar
2、ket-driven standards for the information, entertainment and communications industry. More than 250 companies actively formulate standards in ATIS 20 Committees, covering issues including: IPTV, Service Oriented Networks, Home Networking, Energy Efficiency, IP-Based and Wireless Technologies, Quality
3、 of Service, Billing and Operational Support. In addition, numerous Incubators, Focus and Exploratory Groups address emerging industry priorities including “Green”, IP Downloadable Security, Next Generation Carrier Interconnect, IPv6 and Convergence. ATIS is the North American Organizational Partner
4、 for the 3rd Generation Partnership Project (3GPP), a member and major U.S. contributor to the International Telecommunication Union (ITU) Radio and Telecommunications Sectors, and a member of the Inter-American Telecommunication Commission (CITEL). For more information, please visit . AMERICAN NATI
5、ONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantia
6、l agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made towards their resolution. The u
7、se of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American Natio
8、nal Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards I
9、nstitute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require
10、 that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer Layer 2 is defined in another standard (
11、T1.717-2000). The shaded services shown in the Layer 3 row are not defined in this standard. Physical Layer (PHY)Medium Access Control (MAC) SublayerData Link Control (DLC) SublayerNetwork (NWK)Layer 3Layer 2Layer 1User Service ApplicationsFigure 1 - Reference Model 1.1 Scope This document specifies
12、 the transmit functions of Layer 1 to define the air interface for a Broadband Direct Sequence CDMA system for Fixed Wireless PSTN Access (FWPA). This air interface satisfies the requirements defined in T1.TR.67-2001 for the single-line subscriber architecture. This standard provides the detailed de
13、finition of all component entities within Layer 1, and the services and primitives provided to other layers by Layer 1. ATIS-0700716.2000 2 1.2 Overview Figure 2 shows the interfaces among the lower three layers, and includes a high-level summary of the Layer 1 functionality. Figure 3 shows a block
14、diagram of the PHY, applicable to both the Wireless Access Subscriber Function (WASF) and the Wireless Access Network Function (WANF). The model for this air interface varies from the classical OSI model in the following areas: Data Link Control sublayer (DLC) is limited to data link control of the
15、dedicated control channels. Dedicated traffic channels are not managed by the DLC. MAC, not PHY, performs encoding/decoding for Forward Error Correction (FEC), encipherment/decipherment, symbol repetition/combining, and power control for Quality of Service (QoS). PHY is limited to modulation/demodul
16、ation, spreading/despreading, and RF combining/splitting. The PHY layer performs the following functions: Generation of CDMA codes based on code seeds assigned by higher layers; Synchronization between transmitter and receiver; Generation and transmission of pilot signals; Providing bearers to the M
17、AC layer; and Spreading and transmission of baseband data on a CDMA code specified by the MAC and at a power level specified by the MAC. The PHY provides physical channels (bearers) of 128 Kbps (64 Ksps QPSK). The PHY multiplexes multiple physical channels into the same RF spectrum by the use of dir
18、ect sequence spread spectrum, with a distinct spreading sequence for each channel. The data sequence for each physical channel modulates the spreading sequence, and the resulting sequence modulates the RF carrier. The chip rate of the spreading sequence determines the transmit bandwidth. The Layer 1
19、 receive functions are not specified. The details of the demodulator depend upon the implementation, but must perform the reverse functions to recover the data. Pilot signals are generated by the PHY as necessary and transmitted with the modulated data signals. The pilot signals are intended for syn
20、chronization, carrier phase recovery, and for estimating the impulse response of the radio channel. Pilot signals exist only within the PHY, with the MAC determining the power level. A WASF has a single pilot generator for the uplink pilot signal plus sufficient modulator and demodulator (modem) ins
21、tances for the service in use. A WANF has a single pilot generator for the global pilot signal plus sufficient modem instances for all the logical channels (both global and assigned) in use by all the WASFs being served. ATIS-0700716.2000 3 NWK LayerHigher LayersDLCSublayerMACSublayerPHYLayerAPCCHAC
22、CHTRCH(variablenumberCTAPCCHCTCHAXCH SBCCHFBCCHModulation/Demodulation, Spreading/Despreading, and RF Combining/SplittingPilotGenerationandTrackingDCCHDTCHLayer 3SignallingControlS-APCCHS-ACCHS-TRCH(variablenumber)S-CTAPCCH1S-CTCH1S-AXCH2S-SBCCH1S-FBCCH1SAXPT2LAXPT2GLPT1ASPT2Note:1 Indicates that th
23、e channel exists only in downlink2Indicates that the channel exists only in uplinkControlP-SAPUnspreadPhysicalChannelsPhysicalChannelsFigure 2 - Interfaces Among Layers 1, 2, and 3 ATIS-0700716.2000 4 BasebandfilterMap 0,1to +1,-1BasebandfilterMap 0,1to +1,-1TransmittedSignalcos 2fctsin 2fctI phases
24、preadingcodeQ phasespreadingcodePhysicalchannelpowerlevelsMap 0,1to +1,-1Map 0,1to +1,-1I phasespreadingcodeQ phasespreadingcodePilotpowerlevelPhysicalChannelsPilotSignalPilot power levelMACLayerPHYLayer64 ksym/sperchannelReceivedSignalDemodulatorComplexreceive dataQ dataI dataComplextransmit dataGl
25、obal PN CodeGenerator (seedprovisioned byoperator)Assigned PN CodeGenerator(s)complexspreadingcodescomplexspreadingcodesAssignedcode seedFigure 3 - Physical Layer Model 2 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of t
26、his American National Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards
27、 indicated below. This standard shall be used in conjunction with the following publications: ATIS-0700716.2000 5 T1.717-2000, Air Interface Standard for Broadband Direct Sequence CDMA for Fixed Wireless PSTN Access Layer 2.1ITU-T Recommendation G.823 - The Control of Jitter and Wander Within Digita
28、l Networks Which Are Based on the 2048 Kbps Hierarchy.23 Definitions 3.1 Acquisition Code: Pseudo-noise (PN) code of length 233415 chips generated by the Linear Feedback Shift Register (LFSR). 3.2 Associated Control Channel (ACCH): The assigned channel used for the signaling that is associated with
29、a particular connection. 3.3 APC Channel (APCCH): The assigned channel used to send Automatic Power Control commands from WASF to WANF and from WANF to WASF. 3.4 Automatic Power Control (APC): The feedback processes by which the WANF transmitter uses the minimum transmit power necessary to maintain
30、a link with specified quality to a WASF and the WASF transmitter uses the minimum transmit power necessary to maintain a link with specified quality to the WANF. 3.5 Assigned Channel: A channel assigned for a specific call, as distinguished from a Global Channel. 3.6 Assigned Codes: PN codes that ar
31、e allocated to a set of Assigned Channels (uplink and downlink). 3.7 Assigned Pilot (ASPT): The pilot signal transmitted by a WASF. 3.8 Access Channel (AXCH): A global channel used by the WASF for making an initial access to a WANF. 3.9 Bearer Channel: The resources allocated on the air interface an
32、d PSTN that provide the user service. 3.10 Bit Error Ratio (BER): The ratio of the number of bits received in error to the total number of bits received, also known as Bit Error Rate. 3.11 Bandwidth: The frequency range over which a system spreads its signal; specifically, the chip rate plus the exc
33、ess bandwidth. 3.12 Broadband Direct Sequence CDMA System: A CDMA system utilizing bandwidth greater than or equal to 5 MHz. 3.13 Broadcast Channels: Global channels broadcast from the WANF that provide paging data, access and control channel availability data, service availability and blocking data
34、 to all WASFs. 3.14 CDMA channel: A channel resulting when a 128 Kbps data channel is Direct Sequence spread. 3.15 Chip: One bit in a PN Code. _ 1This document is available from the Alliance for Telecommunications Industry Solutions. 2This document is available from the International Telecommunicati
35、ons Union. ATIS-0700716.2000 6 3.16 Chip Rate: The selected rate at which PN sequences at the WANF and the WASF are clocked. 3.17 Control APC Channel (CTAPCCH): A channel used by a WANF to control WASF transmit power during an access request. 3.18 Control Channel: A global channel used by a WANF to
36、grant access to a WASF. 3.19 Data Channel: A 128 Kbps communications path that will be spread to become a CDMA channel; equivalently, a CDMA channel is despread to become a data channel. This data rate is twice the information rate since all bearer channels are FEC coded to yield a 64 Kbps data rate
37、. 3.20 dBm: A measure of power expressed as a ratio in dB relative to one milliwatt. 3.21 Dedicated Control Channel (DCCH): A higher layer channel containing control plane information for transmission on an assigned channel. 3.22 Dedicated Traffic Channel (DTCH): A higher layer channel containing us
38、er plane information for transmission on an assigned channel. 3.23 Downlink: The radio link from the WANF to WASF. Synonymous with forward link. 3.24 Duplex Method: A method employed to provide simultaneous communication in both uplink and downlink directions. 3.25 Epoch: The repetition period of th
39、e long PN codes is called an epoch. The duration of the epoch is always the same number of chips (29877120), but its length in time is a function of the chip rate. The start of an epoch occurs when the state of the LFSR is equal to its initial state, and the state of the 128 Stage Shift Register is
40、equal to its initial state. 3.26 Excess Bandwidth: The additional bandwidth that together with the chip rate defines the bandwidth of a spread spectrum signal, nominally 20% of the chip rate. 3.27 Fast Broadcast Control Channel (FBCCH): A global channel used by a WANF to broadcast, to all WASFs assi
41、gned to that WANF, fast changing information concerning which services and access channels are currently available. 3.28 Forward Error Correction (FEC): The process of adding additional data to a transmission in order to allow correction of errors by a receiver. 3.29 Forward Link: See Downlink. 3.30
42、 Frequency Division Duplex (FDD): A method of using non-overlapping frequency allocations for the uplink and downlink to achieve full duplex operation. 3.31 Full Duplex: Bi-directional, simultaneous two-way communications. 3.32 Global Channel: A channel not assigned to a specific user or call and di
43、stinguishable from an assigned channel. Global channels consist of the broadcast channels and the Access and Control Channels transmitted by both the WANF and WASFs. Global channels are sometimes referred to as common channels. 3.33 Global Codes: PN codes that are allocated to the Global Channels (u
44、plink and downlink). 3.34 Global Pilot: Downlink pilot signal of length 128, transmitted by a WANF to all WASFs assigned to that WANF. 3.35 Linear Feedback Shift Register (LFSR): Circuit that generates the 233415 chip length PN codes. 3.36 Long Access Pilot (LAXPT): Uplink long code pilot signal use
45、d during access requests. ATIS-0700716.2000 7 3.37 Long Code: PN code of period length 29877120 chips. 3.38 PCS Band: Personal Communication Services frequency allocation defined for operation in the US from 1.85 to 1.99 GHz. 3.39 Pilot Signal: A non-data modulated channel used as a reference for co
46、herent detection and code tracking. The WANF transmits one global pilot signal to all WASFs; each WASF transmits its own set of pilot signals to the WANF. 3.40 PN Code: Pseudo-random, noise-like, periodic chip sequence code used to spread the spectrum of a Data Channel. 3.41 PN Code Seed: The initia
47、l state of the LFSR. A unique seed creates a unique set of codes. 3.42 Processing Gain: The ratio of chip rate to information rate. 3.43 Reverse Link: See Uplink. 3.44 Short Access Pilot (SAXPT): Uplink short code pilot signal used during access requests. 3.45 Short Code: A PN code of length equal t
48、o the Spreading Factor, derived from the long code. 3.46 Slow Broadcast Channel (SBCCH): A global channel used to broadcast slow changing system information and paging messages. 3.47 Spreading Factor: The ratio of chip rate to symbol rate. 3.48 Spreading Code: PN code used to spread the spectrum of
49、a data channel. 3.49 Sub-Epoch: The repetition period of PN sequences from the 36 stage LFSR, equal to 233415 chips. A sub-epoch is 1/128 of an epoch. 3.50 Traffic Channel: A data channel that carries user data at 16, 32, or 64 Kbps (depending on the service). 3.51 Uplink: The radio link in the WASF to WANF direction. Synonymous with reverse link. 4 Acronyms and Abbreviations ACCH Associated Control Channel ACK Acknowledgement ADPCM Adaptive Differential Pulse Code Modulation APC Automatic Power Control APCCH Automatic Power Control Channel
