[Arm-netbook] OpenTag : (Free) Software Defined Radio (was Re: Free Software compatible Hardware for the Internet of Things ? (was CC3000 Wi-Fi for MCU))

Fri Jan 27 10:54:32 GMT 2012

Hello;

To follow up with my previous mail :

"jon.... do you think you could design a FSF-Hardware-Endorseable WIFI
module?"[0]

My reply to this question would simply be no. Because to be able to
have a truly FSF endorseable Wireless Module this one should be based
around a patent free Wireless Standard [1] :

"How is this patent free wireless?

There are probably countless patents surrounding this technology a
court would accept as the basis for a lawsuit. Whether these patents
are actually valid and apply to the respective use would then either
be determined in due time by the legal system, at great cost to both
sides, or the defendant yields to the extortion and accepts the terms
of the plaintiff, reinforcing the business model of the latter.

While it is thus presently impossible to defend ourselves against
patent attacks in general, this risk can be greatly reduced in several
ways. Among the technical choices that affect such risks is the use of
open standards that are not a current hotbed of patent litigation. An
"open standard" means in this context that the specification is
publicly accessible without royalties and confidentiality constraints,
that it can be implemented without (known) licensing requirements or
similar restrictions, and also that suitable hardware (chips, in this
case) can be obtained without undue difficulties.

We consider IEEE 802.15.4 to be currently one of the safest wireless
technologies in this regard."

That's why I would greatly appreciate to highlight the OpenTag project
that could provide a great basis for a FSF endorseable Wireless Module
:

http://www.dash7.org/OpenTag%20Webinar.pdf

Because, not only, OpenTag will provide the invaluable price to be
compatible with the FSF philosophy, but it will also provide a strong
foundation by having a viable underlying business model : to reduce
the costs. As I mentioned in my previous mail, Wifi Modules are mainly
based around ARM9 processors. Especially, the firmware being closed,
it prevents the user to access this computing power and thus it
increases the overall price of the solution with the cost of an
additional MCU [2] :

"-You can use your wireless device as a powerful ARM developement
board, with a 946E core clocked at 30MHz"

OpenTag could be done by the MCU without any additional processor
thanks to its low computational requirements making it an ideal
candidate for (Free) Software Defined Radio.

Hence, I would want to strongly encourage the FSF community to support
the OpenTag project.

Best Regards,

[0] http://lists.phcomp.co.uk/pipermail/arm-netbook/2012-January/002125.html
[1] http://en.qi-hardware.com/wiki/Ben_WPAN
[2] http://lekernel.net/prism54/freemac.html

Guillaume FORTAINE

On Fri, Jan 27, 2012 at 11:20 AM, Guillaume Fortaine
<guillaume.fortaine at devopspace.com> wrote:
> Hello,
>
> First of all, I would like to wish you and the people around you an
> happy new year.
>
> Working on the Internet of Things topic, I have read with a lot of
> interest this thread :)
>
> Especially, I would greatly appreciate to go one step further about
> the Free Software requirements mentioned in it by trying to generalize
> them to the Internet of Things :
>
>
> I) 802.11
>
> But let's start by the beginning with the TI CC3300 Module that,
> according to TI, will be an enabler for the Internet of Things. A
> quick overview at its datasheet will prove you that it is totally
> wrong, given that it doesn't support IPv6 [0].
>
> As well, I have tried to contact the Module manufacturers (LSR and
> Murata) to know if they planned to Open Source the Firmware to give
> people the opportunity to implement IPv6 and, of course, I am still
> waiting a reply.
>
> So, there is clearly a business model, at least in this case, by Open
> Sourcing the firmware. Thus, to complement luke's argumentation, I
> would firstly say that Open Source is clearly an enabler for
> innovation, hence, creating more value-add not only for the
> manufacturer but also for the customer.
>
> One could go further and try to do his own module, with its own
> firmware. Especially, to quote [1]:
>
> "Otherwise, if yu want to implement the WHOLE Firmwarem  (the  specs  are
> free and open) with a small low-power Cortex M3 and the  Maxim  MAX2828,
> MAX2829 or MAX2831 you can do whatever you want..."
>
> Wifi Modules are mainly based around an ARM9 baseband (ARM946E-S core)
> [2] that's why a Cortex-M3 is clearly not up to the task and at least
> a Cortex-M4 (with DSP) [3] would be needed for a mere 802.11b
> throughput. By the way, there have been various attempts to provide
> Open Source Microcodes for WiFi Modules and I will try to list the one
> available to my knowledge below :
>
>
> 1) Lower MAC (LMAC)
>
> a) CARL9170 Firmware Source Repository [4]
>
> "Community AR9170 Linux firmware"
>
>
> b) FreeMAC [5]
>
> "FreeMAC overview
>
> -The goal of this project is to write a firmware for all Conexant
> wireless chipsets from scratch. The advantages are :
> -You will be able to run your wireless station on 100%-free software
> -You can have high-quality wireless drivers, without suffering from
> firmware bugs or limitations that can't be fixed because of
> proprietary licences
> -You can hack whatever feature you want into the firmware
> -You can use your wireless device as a powerful ARM developement
> board, with a 946E core clocked at 30MHz
> -With some electronics skills, you can add whatever you want to your
> wifi card (LCD, keypad, ...). They have an I2C bus which can be easily
> tapped.
> -You can learn how your device works in detail"
>
>
> c) b43-ucode [6]
>
> "OpenSource firmware for Broadcom 43xx devices"
>
>
> d) OpenFWWF [7]
>
> "OpenFWWF, Open FirmWare for WiFi networks, is a project that wants to
> provide an easy and inexpensive platform to implement new Medium
> Access Control (MAC) mechanism, and wants to be a valid alternative to
> simulations and expensive ad-hoc platforms. The combination of
> OpenFWWF and b43 driver is a complete and cheap tool that makes
> testing of new MAC easy achievable."
>
>
>
> 2) Upper MAC (UMAC)
>
> a) Open Source 802.11 API for modules and IC [8]
>
> "Sagrad,  Inc is supporting GPL licensed project with free release of
> the source code that will allow customers unprecedented access to the
> low level radio control.  This low level controlled radio enables a
> host of new applications which have not been possible previously.
> This open source project should lead to an completely open source mac,
> and this project is being supported by a number of large commercial
> companies.  For now, it instantly enables customers to implement
> custom protocols and applications using the low cost silicon normally
> used for 802.11.  This open source project allows many projects to be
> completed with very low cost microprocessor solutions.  Our sample
> code provides a simple pack transmission and reception scheme which is
> interoperable with other 802.11 chip sets but does not yet implement
> connection tracking schemes needed for standard 802.11. Our code base
> fits into one of the smalled STM32 micro processors."
>
>
> Unfortunately, from my point of view, the 802.11 protocol seems to be
> too complicated to be community supported.
>
>
>
> II) 802.15.4
>
> One could argue that there is also 802.15.4 [9] .  Especially, there
> are very interesting Open Source projects around this standard :
>
> 1) Linux
>
> a) Ben WPAN [10]
>
> "Why not just make a WiFi Project (since that is what people are using now)?
>
> The trouble with WiFi is that all the "interesting" chips are
> considered too valuable to give into the hands of the unwashed masses
> without due precautions. Such precautions include niceties like
> handing out hardware design documentation only under NDA, keeping
> register-level interface descriptions under NDA, requiring closed
> sources firmware, only selling large minimum orders through official
> channels, and so on.
>
> All this means that such technology is currently incompatible with the
> goals of copyleft hardware, and would also be expensive to implement
> or, in the case of using modules instead of chips, severely limit our
> design choices.
>
> Things will probably improve in the future (e.g., some chips intended
> for much larger devices than the Ben are already reasonably open), at
> which time it may be relatively painless to add WiFi compatibility.
>
> IEEE 802.15.4 also has several technical benefits over WiFi, including
> much lower power requirements and better spectral efficiency.
> Furthermore, with IEEE 802.15.4 being considerably less complex than
> WiFi, the possibility to migrate from chips with fixed functionality
> to an SDR solution is more likely.
>
> IEEE 802.15.4 is used extensively for sensor networks and similar
> applications, opening the potential of further uses beyond the beaten
> path. (E.g., applications in Domotics.)"
>
>
> b) Linux IEEE802.15.4 stack [11]
>
>
> c) Linux based Wireless Sensor Networks [12]
>
> "The main goal of this project is to involve Linux IEEE802.15.4 stack
> into WSN design."
>
>
>
> 2) MCUs
>
> -uWireless [13]
>
> "Kernel Abstraction Layer
>
> -Support multiple operating systems" [14]
>
>
> But, I would counter-argue that 802.15.4 is flawed by design [15] :
>
> "(N.B. Ironically, 6LoWPAN, a wireless spec written specifically to
> allow IPv6 over low power wireless, is kind of silly, because it is
> 802.15.4 based and hence it is largely incapable of achieving any of
> the useful features of IPv6.)"
>
>
> So, why not to start from scratch as suggested in the top of this post
> and develop a SDR for Microcontrollers with an innovative and FSF
> compatible wireless standard (MAC/PHY) supporting full IPv6 [1] ?
>
> Clearly, the KISS (Keep It Simple Stupid) philosophy is a good basis
> to move forward. That's why, a simple project like Myradio SDR could
> be a potential candidate [16] :
>
> "Myradio is a highly experimental project for implementing a wireless
> PHY and lower-MAC in ATmega8 controllers.
>
> The PHY uses very simple (dumb) radio hardware. I currently use these
> simple modules as lowlevel radio. A simple R2R resistor network is
> used for connecting the PHY microcontroller to the TX radio.
>
> -Does it work?
>
> Yeah, it does sort of work. Valid packets can be transmitted and
> received. You still can't do anything useful with it, however. :)"
>
>
> However, even if this project is great, to have a truly usable SDR
> Module would require a significant engineering effort for the PHY &
> MAC layers.
>
> To be continued ... :-)
>
> Best Regards,
>
> [0] http://e2e.ti.com/support/low_power_rf/f/851/t/159342.aspx
> [1] http://lists.phcomp.co.uk/pipermail/arm-netbook/2012-January/002191.html
> [2] http://wiki.laptop.org/go/Marvell_microkernel
> [3] http://www.st.com/internet/mcu/subclass/1521.jsp
> [4] https://github.com/chunkeey/carl9170fw
> [5] http://lekernel.net/prism54/freemac.html
> [6] http://git.bues.ch/gitweb?p=b43-ucode.git
> [7] http://www.ing.unibs.it/~openfwwf/
> [8] http://www.sagrad.com/opensource/
> [9] http://en.wikipedia.org/wiki/IEEE_802.15.4
> [10] http://en.qi-hardware.com/wiki/Ben_WPAN
> [11] http://linux-zigbee.git.sourceforge.net/git/gitweb.cgi?p=linux-zigbee/kernel;a=shortlog;h=refs/heads/6lowpan
> [12] http://code.google.com/p/linux-wsn/
> [13] http://www.artist-embedded.org/docs/Events/2010/RT_Kernels_Pisa/slides/S4-wireless-Franchino.pdf
> [14] http://www.ipermob.org/files/DemoSAT/afternoon/IPERMOB_SSSA.pdf
> [15] http://dash7.org/blog/?p=1782
> [16] http://git.bues.ch/cms/unmaintained/myradio.html
>
> Guillaume FORTAINE