Changes between Version 14 and Version 15 of 802.11/PHY


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Timestamp:
Dec 2, 2013, 5:18:43 AM (10 years ago)
Author:
murphpo
Comment:

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  • 802.11/PHY

    v14 v15  
    2323== PHY Specs ==
    2424
    25 '''Bandwidth:''' 20MHz
     25'''Clock frequency:''' 160MHz
    2626
    27 '''OFDM Specs:''' 64 subcarriers (48 data, 4 pilots), 16-sample cyclic prefix
     27'''Bandwidth:''' 20MHz max
     28
     29'''OFDM format:''' 64 subcarriers (48 data, 4 pilots), 16-sample cyclic prefix
    2830
    2931'''Frame Format:''' As specified in section 18.3.2 of 802.11-2012:
    3032  * Preamble (10 repetitions of 16-sample short training symbol, 2.5 repetitions of 64-sample long training symbol)
    3133  * SIGNAL field as first OFDM symbol (3 bytes as BSPK, rate 1/2 code)
    32   * Remaining OFDM symbols filled with SERVICE field (2 bytes) and payload (up to 1500 bytes) at one of the rates listed below
     34  * Remaining OFDM symbols filled with SERVICE field (2 bytes) and payload (up to 2048 bytes) at one of the rates listed below
    3335
    3436'''Rates:''' The following OFDM data rates are implemented. Each data rate is realized by a combination of modulation and coding rates.
    … …  
    4345||  64-QAM  ||  3/4  ||  54  ||
    4446
    45 == Receiver ==
     47'''Multi-antenna Support:''' The current PHY Tx/Rx pipelines are SISO, supporting the modulation/coding rates specified in section 18 of the standard. The PHY antenna interfaces implement selection diversity across the two RF interfaces on WARP v3 hardware. The antenna selection is made per packet. For transmissions the antenna selection is always controlled by C code in CPU Low. For receptions the PHY can automatically select the higher-SNR antenna based on the AGC gain selections. Alternatively the C code in CPU Low can force the receive antenna selection.
     48
     49We are also considering implementing some of the MIMO modes from 802.11n/11ac. Let us know if these would be especially useful for your research.
     50
     51----
     52
     53== Receiver Architecture ==
    4654
    4755The architecture of the PHY receiver is illustrated below.
    … …  
    8088The PHY receiver also implements the 1Mbps DSSS rate specified in the original 802.11 standard (section 16.2 of the 802.11-2012 standard). This receiver allows reception of management frames transmitted by 802.11 devices at 1Mbps. These transmissions are common in deployments of 802.11 hardware at 2.4GHz. For example, Beacon and Probe Request frames are frequently transmitted at 1Mbps by commercial devices. The basic STA/AP association handshake requires reception of these frames. The 802.11 Reference Design does not implement a DSSS transmitter, as modern 802.11 devices are able to receive management frames at higher rates (including 6Mbps, the lowest OFDM rate, which is commonly used for management frames at 5GHz).
    8189
    82 === Multi-antenna Support ===
    83 The current PHY Tx/Rx pipelines are SISO, supporting the modulation/coding rates specified in section 18 of the standard. The PHY antenna interfaces implement selection diversity across the two RF interfaces on WARP v3 hardware. The antenna selection is made per packet. For transmissions the antenna selection is always controlled by C code in CPU Low. For receptions the PHY can automatically select the higher-SNR antenna based on the AGC gain selections. Alternatively the C code in CPU Low can force the receive antenna selection.
    84 
    85 We are also considering implementing some of the MIMO modes from 802.11n/11ac. Let us know if these would be especially useful for your research.
     90----