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Doc.: IEEE 802.11-14/0880r1 Submission July 2014 James Wang et. al., MediaTekSlide 1 Increased Network Throughput with Channel Width Related CCA and Rules.

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Presentation on theme: "Doc.: IEEE 802.11-14/0880r1 Submission July 2014 James Wang et. al., MediaTekSlide 1 Increased Network Throughput with Channel Width Related CCA and Rules."— Presentation transcript:

1 doc.: IEEE 802.11-14/0880r1 Submission July 2014 James Wang et. al., MediaTekSlide 1 Increased Network Throughput with Channel Width Related CCA and Rules Date: 2014-07-14 Authors:

2 doc.: IEEE 802.11-14/0880r1 Submission Background and Objectives Raising CCA levels has been shown to increase spatial re-use which leads to significant increase in the network throughput in dense deployment scenarios (ref. 1-10). However, raising CCA levels leads to high collisions This contribution investigates method to alleviate the above issues when raising the CCA levels, thereby increasing the network throughpu This presentation focuses on inter-BSS traffic. (Method of distinguishing inter-BSS traffic and inter-BSS traffic is not included) July 2014 2James Wang et. al., MediaTek

3 doc.: IEEE 802.11-14/0880r1 Submission High Channel Width Transmission Higher channel width transmission is more bandwidth/power efficient –Reduced guard tones (higher number of subcarriers) –Lower rate codes are more powerful July 2014 3 Higher channel width transmission causes less interference in dense deployment environment TX spectral density is lower Same power, different data rates James Wang et. al., MediaTek

4 doc.: IEEE 802.11-14/0880r1 Submission 11ac EDCA TXOP and Channel Access 11ac obtains an EDCA TXOP is based solely on activity of the primary channel (busy or idle conditions) The primary channel is BUSY, if one of the conditions listed in Table 22-27 is met July 2014 4James Wang et. al., MediaTek

5 doc.: IEEE 802.11-14/0880r1 Submission 11ac EDCA TXOP and Channel Access 2 nd ChannelCCA Level Any signal within the secondary 20 MHz channel ≥-62 dBm Any signal within the secondary 40 MHz channel ≥-59 dBm Any signal within the secondary 80 MHz≥-56 dBm 80 MHz non-HT duplicate or VHT PPDU≥-69 dBm 40 MHz non-HT duplicate, HT_MF, HT_GF or VHT PPDU ≥-72 dBm 20 MHz NON_HT, HT_MF, HT_GF or VHT PPDU ≥-72dBm July 2014 5 Transmit channel width determination is based on the secondary channel CCA during an interval (PIFS) immediately preceding the start of TXOP. Secondary channel CCA levels James Wang et. al., MediaTek

6 doc.: IEEE 802.11-14/0880r1 Submission Channel Width Considerations Signal propagation range is determined by the TX spectral density (power/Hz) and the channel propagation loss –Same transmit power, wider TX channel widths  lower TX spectral density  shorter range The baseline (primary channel) CCA levels are based on equal spectral density for all RX channel widths –CCA_Level/channel width (in unit of 20MHz) = -82 dBm for 20, 40, 80, 160 MHz However, the TX spectral density is not the same for all TX channel widths –TX_PWR/20M > TX_PWR/40M > TX_PWR/80M > TX_PWR/160M Narrower TX ch. width transmission interferes (defers) a wider ch. width transmission The likelihood of the wider ch. width transmission is reduced Jan 2014 Slide 6 AP2 20M radius AP1 20MHz PPDU STA1 80 or 160MHz PPDU STA2 6 dB 160 MHz Transmit Spectral Density 80 MHz 9 dB 20 MHz 40 MHz James Wang et. al., MediaTek

7 doc.: IEEE 802.11-14/0880r1 Submission Proposed Enhanced Channel Access for Wider TX Channel Width Transmission -1 Based the CCA Level on the intended TX channel width(s) –Wider intended TX channel width, higher CCA levels July 2014 7James Wang et. al., MediaTek AP1 Intended channel width=80M STA1 STA2 20M @-82dBm 20M @-76dBm 80M @-76dBm STA3 As shown, if AP1 intends to transmit a 80MHz PPDU, it can ignore the 20MHz PPDU by STA1 at -82 dBm. The CCA level for 20MHz PPDU can be raised by 6 dB (from -82 dBm to -76 dBm). This illustration is only for inter- BSS transmission (STA1, STA2, STA3 are OBSS)

8 doc.: IEEE 802.11-14/0880r1 Submission 80 MHz Proposed Enhanced Channel Access for Wider TX Channel Width Transmission - 2 If AP gain channel access for wider channel width transmission with higher CCA level, it should transmit the signal at the same power spectral density as the intended TX channel width July 2014 8 Transmit Spectral Density 80 MHz Reduce the transmit power of 20M and 40M PPDUs such that it has the same power spectral density as 80MHz PPDU used 20 MHz 40 MHz 40 MHz 20 MHz James Wang et. al., MediaTek AP1 Intended channel width=80M 40M PPDU (reduced power) 20M PPDU (reduced power) 20M PPDU As shown AP1 reduces TX power of 20M, 40MHz PPDUs such that it has the same spectral density as 80MHz PPDU (intended TX BW=80MHz) 80 MHz 80M PPDU

9 doc.: IEEE 802.11-14/0880r1 Submission Primary CCA Levels for Different TX Channel Widths Proposed that CCA busy level shall be based on the transmit channel width instead of receive channel width For intended 20 MHz transmission channel width, –CCA for primary 20MHz: -82 dBm –Max tx spectral density = tx power/20MHz For intended 40 MHz transmission channel width, –CCA for primary 20MHz: -8279 dBm –CCA for 40MHz: -79 dBm –Max tx spectral density=tx power/40MHz For intended 80MHz transmission channel width, –CCA for primary 20MHz: -8276 dBm –CCA for primary 40MHz: -7976 dBm –CCA for 80MHz: -76dBm –Max tx spectral density = tx power/80MHz For intended 160MHz (80MHz+80MHz) transmission channel width, –CCA for primary 20MHz: -8273 dBm –CCA for primary 40MHz: -7973 dBm –CCA for primary 80MHz: -7973dBm –CCA for 160MHz: -73dBm –Max tx spectral density = tx power/160MHz Note 1: We only recommend adjusting relative CCA levels based on TX channel widths. We are open to proposals adjusting absolute CCA levels. Note 2: For multiple intended TX channel widths, transmitter can run multiple EDCA queues. July 2014 9James Wang et. al., MediaTek

10 doc.: IEEE 802.11-14/0880r1 Submission Example EDCA Channel Access Transmission Rules In the example, the intended transmit channel width is 80MHz. It is assumed that the device has a transmit power spectral density for the 80MHz transmission is PD 80M (=TX Power/80MHz) and the corresponding CCA level (Slide 7) for 80MHz transmit channel width. Proposed Modified EDCA Channel Access in a VHT BSS for intended Transmit channel width of 80MHz: If a STA is permitted to begin a TXOP (as defined in 9.19.2.3 (Obtaining an EDCA TXOP)) and the STA has at least one MSDU pending for transmission for the AC of the permitted TXOP, the STA shall perform exactly one of the following steps: a)Transmit a 160 MHz or 80+80 MHz mask PPDU if the secondary channel, the secondary 40 MHz channel and the secondary 80 MHz channel were idle during an interval of PIFS immediately preceding the start of the TXOP b)Transmit an 80 MHz mask PPDU at a power spectral density = PD 80M on the primary 80 MHz channel if both the secondary channel and the secondary 40 MHz channel were idle during an interval of PIFS immediately preceding the start of the TXOP c)Transmit a 40 MHz mask PPDU at a power spectral density ≤ PD 80M on the primary 40 MHz channel if the secondary channel was idle during an interval of PIFS immediately preceding the start of the TXOP d)Transmit a 20 MHz mask PPDU at a power spectral density ≤ PD 80M on the primary 20 MHz channel e)Restart the channel access attempt by invoking the backoff procedure as specified in 9.19.2 (HCF contention-based channel access (EDCA)) as though the medium is busy on the primary channel as indicated by either physical or virtual CS and the backoff timer has a value of 0 July 2014 10James Wang et. al., MediaTek

11 doc.: IEEE 802.11-14/0880r1 Submission Transmission based on 80MHz Intended TX Channel Width Illustration of a device run EDCA transmission based on 80MHz intended TX channel width CCA levels (6 dB above current CCA level for 20MHz) 2014/9/6 11James Wang et. al., MediaTek 160MHz

12 doc.: IEEE 802.11-14/0880r1 Submission Conclusions and Future Works Current CCA levels and transmission rules –lower likelihood of high channel width transmission (deferred inappropriately due to out-of-range narrower channel width transmission) Significant network throughput increase can be accomplished in a dense deployment scenarios due to –Higher CCA levels (based on the intended transmission channel width) increase the likelihood of wide channel width transmission –Wider channel width transmission is more bandwidth/power efficiency due to more powerful low rate code and less guard tones Simulation results will be provided in Part 2 of this contribution July 2014 12James Wang et. al., MediaTek

13 doc.: IEEE 802.11-14/0880r1 Submission References 1.Ron Porat, Broadcom, 11-14-0082-00 Improved Spatial Reuse Feasibility - Part I 2.Jinjing Jiang, Marvell, 11-14-0372-00 System level simulations on increased spatial reuse 3.Graham Smith, DSP Group, 11-14-1290-01 Dynamic Sensitivity Control for HEW 4.Graham Smith, DSP Group, 11-14,0294-02 Dynamic Sensitivity Control Channel Selection and Legacy Sharing 5.Imad Jamil, Orange, 11-14-0523-00-00ax Mac Simulation Results for DSC and TPC 6.Graham Smith, DSP Group, 11-14-0328-02 Dense Apartment Complex Throughput Calculations 7.Graham Smith, DSP Group, 11-14-0045-02 E-Education Analysis 8.Graham Smith, DSP Group, 11-14-0058-01 Pico Cell Use Case Analysis 9.Graham Smith, DSP Group, 11-13-1489-05 Airport Capacity Analysis 10.Graham Smith, DSP Group, 11-13-1487-02 Apartment Capacity - DSC and Channel Selection July 2014 Slide 13James Wang et al, Mediatek


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