1、 Part 22: Cognitive Wireless RANMedium Access Control (MAC) and Physical Layer (PHY) Specifications: Policies and Procedures for Operation in the TV Bands Amendment 2: Enhancement for Broadband Services and Monitoring Applications Sponsored by the LAN/MAN Standards Committee IEEE 3 Park Avenue New Y
2、ork, NY 10016-5997 USA IEEE Computer Society IEEE Std 802.22b-2015(Amendment toIEEE Std 802.22-2011as amended by IEEE Std 802.22a-2014) IEEE Standard for Information TechnologyTelecommunications and information exchange between systems Wireless Regional Area Networks (WRAN) Specific requirements ,(6
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4、%XWFK$QWRQ0DGKXVXGDQ%DQDYDUD7XQFHU%DNDV+DUU%LPV1DQF%UDYLQ:LOOLDP%UG(GJDUDQG*7(. whereas, the primary management flowis used by the BS/A-BS or the distributed scheduling A-CPE MAC and CPE MAC to exchange longer, moredelay-tolerant MAC management messages (Table 19 specifies which MAC management messa
5、ges aretransferred on which type of connections). Finally, the secondary management flow is used by the BS/A-BSor the distributed scheduling A-CPE and CPE to transfer more delay-tolerant, standards-based (e.g., DHCP,TFTP, and SNMP) messages that are carried in IP datagrams. The secondary management
6、flow may bepacked and/or fragmented, similarly to the primary management except that no ARQ should be used for thelatter since it is more time critical.Change the now seventh paragraph of 7.2 as follows:Many higher-layer sessions may operate over the same wireless connection. For example, many users
7、within a company may be communicating with Transmission Control Protocol (TCP)/IP to differentdestinations, but since they all operate within the same overall service parameters, all of their traffic ispooled for request/grant purposes. A service flow is a unidirectional flow of traffic (BS/A-BS to
8、CPE, orCPE to BS/A-BS, distributed scheduling A-CPE to CPE, or CPE to distributed scheduling A-CPE) thatdefines the mapping of higher-layer application service parameters (e.g., QoS) to a FID assigned to aparticular CPEs unicast SID or multicast group (multicast SID).7.3 General superframe structure
9、Insert the following paragraphs as the first three paragraphs of the preliminary text in 7.3:The A-WRAN supports two PHY operation modes: PHY Operation Mode 1 (PHY-OM1, Clause 9) andPHY Operation Mode 2 (PHY-OM2, Clause 9a).The WRAN system and the A-WRAN system on PHY-OM1 shall support the following
10、 superframestructure.The A-WRAN on PHY-OM2 does not support the following superframe structure.Change the now fourth paragraph of the preliminary text in 7.3 as follows:The IEEE 802.22 WRAN system and the A-WRAN system on PHY-OM1 includes two operational modes:a normal mode and a self-coexistence mo
11、de. In normal mode, one WRAN/A-WRAN cell occupies one ormore channels and operates on all the frames in a superframe. In self-coexistence mode, multiple WRANand/or A-WRAN cells share the same channel, and each coexisting WRAN and/or A-WRAN cell operateson one or several different frames exclusively.
12、Change the title of 7.4 as follows:7.4 General frame structure (on PHY-OM1)Insert the following paragraph as the first paragraph in 7.4:The WRAN system and the A-WRAN system on PHY-OM1 described in Clause 9 shall support thefollowing frame structure.IEEE Std 802.22b-2015IEEE Standard for Wireless Re
13、gional Area NetworksPart 22: Cognitive WRAN MAC and PHY Specifications: Policies and Procedures for Operation in the TV BandsAmendment 2: Enhancement for Broadband Services and Monitoring Applications8Copyright 2015 IEEE. All rights reserved.Insert the following subclauses (7.4a and 7.4b and their s
14、ubclauses, figures, and tables) after 7.4:7.4a General frame structure (on PHY-OM2)The A-WRAN on PHY-OM2 described in Clause 9a shall support the following frame structure.The A-WRAN on PHY-OM2 includes two operational modes: a normal mode and a self-coexistence mode.In normal mode, one A-WRAN cell
15、occupies one or more channels and operates on all the frames. In self-coexistence mode, multiple A-WRAN cells share the same channel, and each coexisting WRAN celloperates on one or several different frames exclusively.The A-WRAN on PHY-OM2 shall transmit the Frame Control Header (FCH) (7.5.2a, Tabl
16、e 2a) at thebeginning of every frame on the operating channel in both normal mode and self-coexistence mode. An A-WRAN runs in normal mode by default and transits to self-coexistence mode when the A-WRAN can detectand decode an FCH or a CBP from an adjacent A-WRAN cell on its operating channel.7.4a.
17、1 General frame structure for normal modeThe A-WRAN frame structure depicted in Figure 12 shall be used and the first frame shall be constituted ofthe following: A PHY frame preamble (Clause 9a) A Frame Control header (FCH) (7.5.2a) The rest of the first frame including its frame header and data pay
18、loadAt the beginning of every frame, the A-BS shall transmit the frame preamble and the FCH on the operatingchannel using the modulation/coding specified in 9a.2 and Table 231e, respectively. In order to associatewith an A-BS, a CPE must receive the FCH to establish communication with the A-BS. Duri
19、ng each MACframe, the A-BS shall manage the upstream and downstream operations, which may include ordinary datacommunication, measurement activities, coexistence procedures, and so on.7.4a.2 General frame structure for self-coexistence modeThe A-WRAN frame structure in self-coexistence mode is shown
20、 in Figure 13a. The self-coexistence modeis for the scenario when multiple A-BSs with overlapping coverage have to share the same channel. Thefrequency reuse factor cannot be maintained as one due to the mutual interference of these A-BSs. In thiscase, the A-BSs shall share the channel on a per-fram
21、e basis, i.e., each A-BS is allocated the frames on anon-interference basis. The negotiation process of frame allocation can be found in 7.20.In self-coexistence mode, the A-BS and CPEs in an A-WRAN cell shall transmit only during the activeframes allocated to that A-WRAN cell. They can transmit dur
22、ing other frames only when a self-coexistencewindow (SCW) has been scheduled. During the frames not allocated to the present cell, the A-BS and CPEsmay monitor the channel for any transmission from neighboring A-WRAN cells to improve self-coexistence.7.4a.3 Frame formatThe A-WRAN system on PHY-OM2 d
23、escribed in Clause 9a shall support the following frame structure.The top-down time division duplex (TDD) frame structure employed in the MAC is illustrated in Figure 12.IEEE Std 802.22b-2015IEEE Standard for Wireless Regional Area NetworksPart 22: Cognitive WRAN MAC and PHY Specifications: Policies
24、 and Procedures for Operation in the TV BandsAmendment 2: Enhancement for Broadband Services and Monitoring Applications9Copyright 2015 IEEE. All rights reserved.As illustrated in Figure 13b, a frame comprises two parts: a downstream (DS) subframe and an upstream (US)subframe. A portion of the US su
25、bframe may be allocated as a window to facilitate self-coexistence. ThisSCW may be scheduled by the A-BS at the end of the US subframe when necessary to allow transmission ofopportunistic coexistence beacon protocol bursts. The SCW includes the necessary time buffers to absorbthe difference in propa
26、gation delay between nearby and distant A-BSs and CPEs operating on the samechannel. The boundary between the DS and US subframes shall be adaptive to adjust to the DS and USrelative capacity. The US subframe may contain scheduled US PHY PDUs, each transmitted from differentCPEs for their US traffic
27、. It may also include contention intervals scheduled for the following: CPE association (initial ranging) CPE link synchronization, power control, and geolocation (periodic ranging) Bandwidth request Urgent coexistence situation (UCS) notification Quiet period (QP) resource adjustmentThe definitions
28、 of the fields/messages are given in 7.6 and 7.7.The PHY PDUs may be transmitted across several subchannels as shown in Figure 13b, which depicts howa frame may be transmitted (in time and frequency) by the PHY.Figure 13b shows an example of the two-dimensional (2D) (time/frequency) structure of the
29、 MAC framethat shall consist of an integer number of fixed-size OFDM slots. Each slot shall consist of 4 OFDMsymbols by one subchannel (i.e., 1 OFDM slot for DS = 4 symbols 1 subchannel) for DS and shall consistof 7 OFDM symbols by subchannel (i.e., 1 OFDM slot for US= 7 symbols 1 subchannel) for US
30、(9a.1.3.1). A subchannel consists of 16 subcarriers. In Figure 13b, the MAC packets are assumed to bestructured in a linear TDM manner (see Figure 12), and the PHY packets are arranged in a 2D time/frequency domain (symbol in the horizontal direction, logical subchannels in the vertical direction).
31、For theFCH, DS/US-MAP, DCD, UCD, and DS payload, the MAC information is first laid vertically bysubchannels and then stepped horizontally in the time direction. This vertical layering allows earlyscheduling of DS bursts assigned to distant CPEs to compensate for propagation delays and to avoidpotent
32、ial interference at the CPE if overlapping A-WRAN cells with different DS/US capacity split.Frame 10msFrame preambleFCHFrameFrame preambleFCHFrameFrame preambleFCHA-WRAN0A-WRAN1Figure 13aGeneral frame structure on PHY-OM2 for self-coexistence modeIEEE Std 802.22b-2015IEEE Standard for Wireless Regio
33、nal Area NetworksPart 22: Cognitive WRAN MAC and PHY Specifications: Policies and Procedures for Operation in the TV BandsAmendment 2: Enhancement for Broadband Services and Monitoring Applications10Copyright 2015 IEEE. All rights reserved.The MAC data elements, starting from the FCH and including t
34、he first broadcast burst, shall be enteredinto the portion between the second OFDM symbol and fifth OFDM symbol, which is based on the numberof symbols defined in a tile (9a.1.3.1), as shown in Figure 13b, in the increasing order of logical subchannelsuntil all logical subchannels are occupied. Then
35、, the subsequent data elements, if they have not all beenmapped, shall be placed in the same order on the following OFDM symbols. The balance of the lastOFDM symbols shall be padded with zeros. The modulation and coding schemes for the padding zeros aredefined by the DIUC for the last DS burst in th
36、e DS-MAP. Note that the DS-MAP indicates the length ofthe contiguous DS MAC elements, not their absolute position in the DS subframe.The MAC data elements that are contained in US bursts shall be mapped to the US subframe in a differentorder as shown in Figure 13b. They are first mapped horizontally
37、, 7 OFDM symbols by 7 OFDMsymbols, in the same logical subchannel. Once a logical subchannel has been filled to the end of theUS subframe, the balance of the MAC data elements shall be mapped to the next logical subchannel, in anincreasing subchannel order. This process continues until all of the su
38、bchannels and symbols allocated tothe burst are filled. If the quantity of MAC data elements is insufficient to fill an US burst so that aninteger number of OFDMA slots is occupied once encoded, zero padding shall be inserted at the end.Alternatively, the horizontal laying of the MAC data elements m
39、ay fill one subchannel with at least 7OFDM symbols at a time and continue on the following subchannels. However, when all logicalsubchannels have been filled, the next MAC data elements shall be placed in the first available logicalsubchannel in the following burst. The width of the last vertical bu
40、rst will be between 7 and 13 symbolsdepending on the total number of symbols in the US subframe.The long US packet structure, where a logical subchannel is completely filled before moving to the nextsubchannel, is used to maximize the allowed power per subcarrier for a given CPE EIRP limit, i.e., th
41、ishorizontal laying reduces the EIRP required by the CPE for its US burst by minimizing the number ofFrame preambleFCHDSMAPUSMAPUSMAPDCDUCDBurst 1BurstsBurstmRanging/BW request/UCS notificationBurst 1BurstBurstBurstBurst nBurstsBurst 2Self-coexistence WindowDS subframe US subframeTTGRTGFrame 0 Frame 1 . Frame 1510msFrame preamble FCHSymbols12345678910 XX-1X-2X-3X-4X-5 X+5X+4X+3X+2X+1 X+9X+8X+7X+6 Y-2Y-3Y-4Y-5Y-6 YY-1Burst 1SubchannelsFigure 13bExample of a time/frequency structure of a MAC frame for PHY-OM2
