Re: 802.11 10Mhz Channel

> Hi Ruben,
>
> The preliminary modifications we plan to introduce are only related with
> the adaptation of some PHY parameters to model a 10Mhz channel and their
> data rates (3-27Mbps). Since these changes are actually based on the
> current WiFi model we don’t think that any validation would be needed
> (correct me if I am wrong). However, when in the future we introduce new
> error rate models (BER look-up tables obtained from simulink and
> considering mutipath channels) for the vehicular environment we will
> necessary have to validate our models. For the time being, it is
> difficult for us to say how we will validate the models since the
> 802.11p technology is in its early stages and there no exist too much
> work to validate our future models against.

> As soon as we proceed with our validations plans I will let you know.
>
> Regards,
>
> Ramon.
>
>
>
> 2009/5/29 Ruben Merz <ruben@...
> <mailto:ruben@...>>
>
>     Hi Ramon,
>
>     How do you plan to validate your phyical layer implementation?
>
>     Ruben
>
>     Ramon Bauza wrote:
>      > 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
>      >
>     ----------------------------------------------------------------------------
>
>     --
>     Ruben Merz                   Deutsche Telekom Laboratories
>     http://www.net.t-labs.tu-berlin.de/people/ruben_merz.shtml
>
>
>
>
> --
> --------------------------------------------------------------------------
> 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
> ----------------------------------------------------------------------------