LwMesh Questions

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Hi, I am really happy to find such a great forum. I have some questions about LwMesh, please:

1)I intended to make a synchronized Mesh network with 802.15.4, then I understand that 802.15.5 is a version of Mesh networking of 15.4. So I decided to implement just about 802.15.5. Fortunately, It seems LwMesh would simplify my task and I can use it kind of instead 802.15.5 for Mesh Networking, right?

2) Does LwMesh has functions for synchronization among devices to make them periodically fall into sleep in order to save energy when they aren't busy?

3) Since LwMesh doesn't include MAC of 802.15.4, does it have any MAC mechanism or we should add a specific one?

4) If I start with ATMega128 and ATZB-RF-233-1-C to implement LwMesh, will I be able to simply change the processor to a more efficient and stronger one such as ATSAM20/21?

5) Does the "Mesh networking capability" mentioned in RF-233 datasheet refer to LwMesh stack? or it does something else?

Cheers,
Mohamad

[mod: please create separate topics instead of reusing the generic one]

Last Edited: Fri. Oct 16, 2015 - 12:24 AM
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Mohamad84 wrote:
1)I intended to make a synchronized Mesh network with 802.15.4, then I understand that 802.15.5 is a version of Mesh networking of 15.4. So I decided to implement just about 802.15.5. Fortunately, It seems LwMesh would simplify my task and I can use it kind of instead 802.15.5 for Mesh Networking, right?
That depends on what you understand by "synchronized". But most likely LwMesh will work for you.

Mohamad84 wrote:
2) Does LwMesh has functions for synchronization among devices to make them periodically fall into sleep in order to save energy when they aren't busy?
No, but your application is free to implement this. If you want something like sleeping routers, then it gets more complicated.

Mohamad84 wrote:
3) Since LwMesh doesn't include MAC of 802.15.4, does it have any MAC mechanism or we should add a specific one?
You don't need MAC with LwMesh.

Mohamad84 wrote:
4) If I start with ATMega128 and ATZB-RF-233-1-C to implement LwMesh, will I be able to simply change the processor to a more efficient and stronger one such as ATSAM20/21?
Depends on how you write your application. If you will write portable code, then yes, there should be no problems doing that.

Mohamad84 wrote:
5) Does the "Mesh networking capability" mentioned in RF-233 datasheet refer to LwMesh stack? or it does something else?
I don't think it refers to any particular stack. RF233 itself does nothing to support mesh, it is just a radio.

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Mohamad84 wrote:
4) If I start with ATMega128 and ATZB-RF-233-1-C to implement LwMesh, will I be able to simply change the processor to a more efficient and stronger one such as ATSAM20/21?

Note that ATSAMD21 + AT86RF233 = ATSAMR21...

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The ATZB-RF-233-1-C is a certified module with a chip antenna rather than just an IC

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Thank you alexru, awneil, ramlco
I meant time synchronization between nodes for sleeping and energy purpose. I think the TWO main functions in an energy efficient mesh network are Time Synch and Routing, and LwMesh do only one. Any Idea?

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LwMesh does not do time synchronization. And I don't know any generic protocols that do. OpenWSN might have it, but that would be up to you to figure out hoe to run that mess.

Do you have specific requirements in mind?

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"efficient mesh network" is a very broad and generic term. Time-synchronized networks have many problems, they are much harder to setup.

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I want to finally design a Wireless Mesh and Ad-hoc Network for Multi-hop voice communication and every device functions as both router and end user. If synch and sleep mechanism is not utilized, the energy of the devices will be quickly finished. So If I can implement a good synch technique it will be a big deal, will not?

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It is hard to transfer voice over standard IEEE 802.15.4 in one hop. Doing so in a mesh is next to impossible.

I think you need to start from bandwidth requirements calculations.

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There are some modules supporting 802.15.4 and with a rate of 2Mbps. I want to use them. such as ATZB-RF-233-1-C.

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2 Mbps mode has limitations that render is pretty much useless for mesh networks. One of the limitations is LQI not working properly in that mode, but there are others.

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However, I think 1Mbps would be enough, I probably should do my work without LQI function. Do you think LQI is an main function for my work?

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That's the only reasonable way I know to build and maintain a mesh network. LwMesh 100% relies on it and will not work without proper LQI values.

You really need to do realistic calculations. How many devices you expect to have in the network? How many of them will transmit at the same time? What is anticipated bandwidth requirement for your codec?

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I expect to have about 20 devices and at least 2 communications (4 devices) should be able to transmit, at the same time, which may cross each other. and about 16-32 Kbps bandwidth is expected for codec. Doesn't LQI properly work in 1Mbps?

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No, it does not work in any mode except for a standard 250 Kbps.

But if you want to transfer voice, then mesh gets complicated anyway. In non-time synchronized mode you will have unpredictable (and significant) delays, so you will have to implement some sort of synchronization and disable CSMA mechanism.

The problem is that I've never seen a generic mesh protocol for time-synchronized networks. It is very hard to do slot allocation in a non-conflicting manner.

On the other hand, for 20 nodes it should be possible to come up with some simple application-specific protocol.

Don't expect it to be easy, a lot of trial and error will be involved.

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OK, Good Advice,
I should think how I can deal with the problems.
Thank you so much Alex

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Hi,
How much is the minimum programmable flash of the Micro-controller required for running LwMesh?

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Depends on your configuration typically 8-12 kB. It says so in the first post of this thread.

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HI ,

 

I am currently planning to deploy a smart mesh network communication, a kind of proof of concept thing. I am bit confused over choosing the right hardware for it. I need a total development kit with mesh network stack available and inbuilt RF transceiver. Found two kits like the SAM R21 Xplained Pro Evaluation Kit(but i guess it doesn't support mesh network stack) and the ATmega256RFR2 Xplained Pro Evaluation Kit.   Pease suggest me a right hardware for the development.

 

 

Thanks

Sriram

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Sriram@Atmel wrote:
SAM R21 Xplained Pro Evaluation Kit (but i guess it doesn't support mesh network stack)

What makes you think that?

 

http://www.atmel.com/tools/atsam...

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Last Edited: Fri. Apr 17, 2015 - 01:10 PM
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@awneil,

 

http://www.atmel.com/tools/LIGHT...

 

It says that currently the stacks works  with AVR®-based MCUs. But the stack can be ported on all other devices. I Just have no idea how easy the porting to other MCS's will be??

 

 

 

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That's out-of-date, then!

 

It has support for SAM D20 & D21 - the R21 is just a D21 with an AT86RF233 in the same package.

 

APPLICATION NOTE AVR2130: Lightweight Mesh Developer Guide; Rev G, 03/2014 wrote:
Lightweight Mesh is designed to work with all Atmel IEEE® 802.15.4 transceivers and SoCs. Currently the stack works with AVR® - and ARM® -based MCUs, but given extreme portability and low resource requirements, it can be run on almost any Atmel MCU. A full list of supported platforms can be found in the Lightweight Mesh Getting Started Guide 

http://www.atmel.com/Images/Atme...

 

http://www.atmel.com/Images/Atme...

 

Interestingly enough, the Getting Started guide lists the SAMD20 Xplained Pro and SAMR21 Xplained Pro - but not SAMD21 Xplained Pro!

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Last Edited: Fri. Apr 17, 2015 - 02:20 PM
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As noted here https://www.avrfreaks.net/forum/a... there are quite a lot of historical references to "AVR" which should now read "AVR & ARM" throughout Atmel's documentation...

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Hi,

 

I'm planning to use atmel's LwMESH  for my POC on wireless mesh networks. I have few question regarding the stack. I understand that the stack works only on the atmel MCU's. 

1. What are the communication medium does the stack work along, like does it work on Zigbee Pro or 6LOWPAN?

2. How many nodes(MCU's) are required to form the mesh network with the stack?

3. The user guide states that no special joining procedure is required for the nodes to start communicating and also Network management (discovery, joining, commissioning, etc) should be taken care  by the application. Can anyone please brief me on this?

4. Do i have an readily available eval kit comprising of H/W's required for the mesh n/w(Co-ordinator, router and end nodes)?

5. Out of curiosity- do atmel have an network analyser tool that helps to monitor and analyse the mesh network over GUI(with Atmel studio- avr framework)

 

Thanks

Sriram

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Sriram@Atmel wrote:
POC

What's a "POC" ?

 

Proof Of Concept?

 

Quote:
I understand that the stack works only on the atmel MCU's

No - it's just that the licence terms only permit it to be used on Atmel MCUs.

 

Quote:
1. What are the communication medium does the stack work along, like does it work on Zigbee Pro or 6LOWPAN?

It is a proprietary protocol over IEEE 802.15.4

 

Have you looked at the documentshttp://www.atmel.com/tools/light... - eg, the Getting Started Guide has a list of ready-to-go targets...

 

 

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Hi Awneil,

 

Thanks for your speedy reply. POC  is proof of concept.

It is a proprietary protocol over IEEE 802.15.4 means that it does not support zigbee ? the medium of communication is just by radio?

and there is no zigbee pro mesh network?The getting started doc mentions the zigbit modules as the target , so i'm bit confused.kindly clarify my doubts.

 

Thanks'

siram

 

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Sriram@Atmel wrote:
It is a proprietary protocol over IEEE 802.15.4 means that it does not support zigbee ?

Zigbee is a protocol which runs over IEEE 802.15.4;

LwMesh is an entirely different protocol which also happens to run over IEEE 802.15.4;

And there are many other protocols which also happen to run over IEEE 802.15.4.

 

https://en.wikipedia.org/wiki/IE...

 

the medium of communication is just by radio?

Yes.

 

and there is no zigbee pro mesh network?

Not in LwMesh.

 

The getting started doc mentions the zigbit modules as the target , so i'm bit confused.kindly clarify my doubts.

Why are you confused? What "doubts" do you have

 

Are you assuming that the "zig" in "zigbit" somehow means "Zigbee" ?

 

Have you studies the zigbit documentation?

ZigBit modules are compact 802.15.4-based wireless modules

 

http://www.atmel.com/products/wi...

 

The modules just provide the hardware IEEE 802.15.4 layer - you add software to that to give you Zigbee or LwMesh or whatever

 

http://www.atmel.com/products/mi...

 

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Sriram@Atmel wrote:
1. What are the communication medium does the stack work along, like does it work on Zigbee Pro or 6LOWPAN?
As mentioned earlier, it implements its own protocol.

 

Sriram@Atmel wrote:
2. How many nodes(MCU's) are required to form the mesh network with the stack?
Just one really, it will be a silly network, but it will be a network.

 

Sriram@Atmel wrote:
3. The user guide states that no special joining procedure is required for the nodes to start communicating and also Network management (discovery, joining, commissioning, etc) should be taken care  by the application. Can anyone please brief me on this?
It is a huge topic, you will have to be more specific.

 

Sriram@Atmel wrote:
4. Do i have an readily available eval kit comprising of H/W's required for the mesh n/w(Co-ordinator, router and end nodes)?
Virtually any Atmel wireless kits is supported or can be supported after simple porting procedure. Kits that already supported are listed in the documentation.

 

Sriram@Atmel wrote:
5. Out of curiosity- do atmel have an network analyser tool that helps to monitor and analyse the mesh network over GUI(with Atmel studio- avr framework)
There is a Wireshark interface in the Atmel Studio.

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Thanks awneil and  alexru. 

 

Suppose I have 50 nodes to be connected into mesh network, do i require a special procedure to be carried out with all the 50 nodes for joining ,discovery and commissioning or the nodes forms a mesh by itself as soon as the nodes are powered on? The automatic discovery of the paths will be taken care in the stack ?

 

Thanks

Sriram

 

 

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You will have to at least preconfigure each of them with a unique address.

 

If you can't do that (and most applications can't), then you will have to implement a commissioning procedure appropriate for your application.

 

After nodes are configured with individual addresses, the route discovery happens automatically.

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Thanks Alex.

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Hi,

 

I have 5 zigbee modules and samd21 xplained pro kit. Can I  form a  mesh network with the zigbee modules using LWmesh stack or by any other means?Any idea to form a mesh network?

 

Thanks

Sriram

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What "zigbee modules" are they, exactly?

 

Have you studied their documentation to see what that says about loading custom firmware?

 

Did you read post #27 ?

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Last Edited: Wed. Jul 8, 2015 - 09:27 AM