Re: 802.11 10Mhz Channel

> Hello everyone,
>
> I am Ramon Bauza, a researcher at Miguel Hernandez University (Spain).
> Currently, I am involved in the EU FP7 project iTETRIS which aims at
> creating an integrated traffic and wireless simulation platform that will
> allow evaluating traffic management strategies and communication protocols
> in vehicular environments. The iTETRIS project employs SUMO and ns-3 as
> traffic simulation and wireless simulation platforms respectively.
>
> Our research group at UMH, it is charge of implementing the 802.11p (WAVE)
> standard in ns-3. 802.11p is based on 802.11a, being the channel bandwidth
> and thus also the data rates the main differences between both (802.11p uses
> a 10Mhz whereas 802.11a uses 20Mhz). After implementing 802.11p in ns-3, we
> will also look into and implement propagation models for vehicular
> environments that consider LOS/NLOS visibility conditions,
> vehicle-to-vehicle and vehicle-to-infraestructure communications, and
> shadowing and multipath fading effects.
>
> In order to model a 10Mhz channel in ns-3, some additions/modifications
> should be done (some weeks ago I posted a message in the user mailing list
> regarding this
> http://groups.google.com/group/ns-3-users/browse_thread/thread/f27b1ddcf9f1d532#).
> Apart from 802.11p, I think other 802.11 standards employ 10MHz channels and
> thus probably the modeling of 10Mhz channels would also be useful for the
> ns-3 community working on 802.11-related topics. In fact, the IEEE Std
> 802.11TM-2007 standard considers 10Mhz channel spacing using OFDM. If you
> consider that the modeling of 10Mhz channels may be beneficial for other
> users we would be glad to merge the 10Mhz modeling in the main branch.
>
> Below, I compile the needed functions and modifications we plan to
> introduce in ns-3 at the PHY layer for modeling a 10Mhz channel:
>
> + wifi-phy-standard.h
>
>   Add WIFI_PHY_STANDARD_80211_10Mhz in the enum WifiPhyStandard
>
> + wifi-phy.h and wifi-phy.cc
>
>   Declare and define the following new functions:
>
>     static WifiMode Get3mb10Mhz (void);
>     static WifiMode Get4_5mb10Mhz (void);
>     static WifiMode Get6mb10Mhz (void);
>     static WifiMode Get9mb10Mhz (void);
>     static WifiMode Get12mb10Mhz (void);
>     static WifiMode Get18mb10Mhz (void);
>     static WifiMode Get24mb10Mhz (void);
>     static WifiMode Get27mb10Mhz (void);
>
> + yans-wifi-phy.h and yans-wifi-phy.cc
>
>   Declare and define the void Configure80211_10Mhz (void) function.
>   Modify the void SetStandard (enum WifiPhyStandard standard) function so
> that the user can also select a 10Mhz channel.
>
> + interference-helper.h and interference-helper.cc
>
>   Declare and define void Configure80211_10MhzParameters (void);
>
> One function that should be modified is
> InterferenceHelper::CalculateTxDuration (uint32_t size, WifiMode
> payloadMode, WifiPreamble preamble) const since it assumes that the symbol
> duration is always 4us (20 Mhz channel). This function should employ a
> symbol duration according to the channel used (10Mhz or 20Mhz). One possible
> solution to solve this would be to have a new variable in the class
> InterferenceHelper which allows differentiating the channel used. This
> variable could be of type WifiPhyStandard. In the function Time
> InterferenceHelper::CalculateTxDuration, this new variable would be examined
> and the packet txon duration will be calculated based on the bandwidth
> channel.
>
> Please, I would like to have your comments on this in order to proceed with
> the implementation.
>
> Thank you in advance.
> Best regards,
> Ramon.
>
> --------------------------------------------------------------------------
> Ramon Bauza
> Ubiquitous Wireless Communications Research Laboratory
> Uwicore, http://www.uwicore.umh.es
> Signal Theory and Communications Division
> University Miguel Hernández (Spain)
> Tel: +34 96522 2031
> Fax: +34 96665 8903
>
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