[Ovmsdev] USSD Signaling

Wed Aug 21 09:13:49 HKT 2013

To me, it comes down to:
  a) Ease of setup (I think we all agree it is way to complex at the moment)
  b) Predictable cost

In Hong Kong, I pay about US$2.5 a month for 50MB. Beyond 50MB I'd have to pay extra, but something would have to be seriously wrong with OVMS for that to happen.

I have heard reports of early firmware OVMS units continuously trying to connect to the server, driving up GPRS costs. This happens when the server password is incorrect, and is aggravated by cellular networks that round-up to the nearest 100KB or 1MB per connection! More recent OVMS firmware has exponential backoff for connection attempts and tries to keep the GPRS connection open unless absolutely necessary, so does not suffer from this as badly. The server now also alerts (via push notification) if it sees a bad connection attempt. However, from server logs we can still see repeated incorrect authentication requests from a particular vehicle go on for days at a time.

I tried doing an auto-provisioning system for OVMS, but it was just too complex. Hundreds of different cellular providers, all with different GPRS settings. GeoSIM is easier, but still different in some countries (Italy, UK, etc).

Given that I'm now paying US$30/year, would I pay US$96-US$120? With the multi-sim-card shared-data plans coming out now, the price of an extra SIM for OVMS is coming down to $0/year, so I am really not sure.

I currently get about 1 call for help for every 10 OVMS installations. I'm not sure how many calls are avoided by local users helping each other out, but I do know that in the early days of OVMS it was 10 calls for 10 installations! I've had just 1 RMA replacement in the past year.

Almost every call I get at the moment is the result of incorrect authentication credentials. Either the vehicleid or server password is incorrect, most of the time. Sometimes things are connected just fine, but the vehicleid has not been configured, or CAN_WRITE enabled, etc.

I do really like the idea of extending that vehicle details form on www.openvehicles.com with the SIM serial number, and having the module automatically configure itself 100%. Damn, that would be nice! And for the less technically competent users, so very much simpler. Is that option worth adding US$10 to the price of the module (by bundling a USSD-capable SIM, even if it is never used)?

Regards, Mark.

On 21 Aug, 2013, at 5:14 AM, Dominik Westner <me at nikwest.de> wrote:

> Hi Kevin,
> 
> I only used three as an example. The point I was trying to make is that you don't need any special data tariffs. At least in Europe a plain SIM with no data plan is the best as the OVMS traffic is really really low.
> 
> I am also not sure what you are exactly talking about. Do you mean you are swapping SIMs in the OVMS device? I am not sure why would you do that? At least in EU countries the cost of data traffic is heavily regulated. It will cost you 46 cent per MB with 1kb minimum data size. This additional cost almost goes unnoticed on your bill for the OVMS SIM even when you are travelling a lot. Coverage while roaming should not really depend much on your SIM provider I think.
> 
> At least in Europe I don't think cost is a burden. But I agree, that configuration right now is not so easy and anything which makes it easier would be welcome. Although personally I wouldn't switch to USSD if it has a considerably higher cost.
> 
> Dominik
> 
> On Aug 20, 2013, at 9:54 PM, Kevin Sharpe ZCW <kevin.sharpe at zerocarbonworld.org> wrote:
> 
>> Dominik,
>> 
>> Three has pretty poor network coverage in the UK and would be of limited use to most OVMS users here.
>> 
>> I tried GeoSIM but results were not great and I would need to keep an unlocked phone with me for traveling around Europe. Indeed on my most recent trip I would be swapping the sim several times a day moving in and out of various countries.
>> 
>> Today I use a giffgaff sim which runs on the 02 network. It costs me £5 per month and provides great coverage in the UK and most of Northern Europe. Only time I've ever had problems with giffgaff is in Switzerland (I didn't have an unlocked phone with me)
>> 
>> Anything that reduces the burden of support is a good thing especially if we wish to grow the number of OVMS users significantly.
>> 
>> Kevin Sharpe
>> 
>> On 20 Aug 2013, at 17:13, "Dominik Westner" <me at nikwest.de> wrote:
>> 
>>> @Nikki:
>>> 
>>> if you pay £6 a month in the UK it looks like you have the wrong data plan. The trick for low monthly rates is to have no data plan at all and pay per MB. This should be between 10p - 30p in the UK (just glimpsed at the 3 web site). With this you'll never pay more than £2 a month. Even when doing a 4 weeks trip through Europe I highly doubt that this will be more than £6 a month. I NEVER paid more than 2EUR per month for the last 15 months and my cost is 23 cents per MB (1KB min data size).
>>> 
>>> Sorry, don't want to get off topic though.
>>> 
>>> If we go USSD this also implies some sort of vendor lock in with the M2M provider as he has to do the routing.
>>> 
>>> Dominik
>>> 
>>> 
>>> On Aug 20, 2013, at 3:32 PM, Nikki Gordon-Bloomfield <nikki at aminorjourney.com> wrote:
>>> 
>>>> I pay WAY over for mine (£6 a month for data only sim) but that's because I want the continued knowledge that my cost is predictable every month. Considering I've heard (though I can't remember where) that Nissan wants £100 a year for Carwings after third year, I'm happy with that...
>>>> 
>>>> Nikki. 
>>>> 
>>>> On 20 Aug 2013, at 14:26, Mark Webb-Johnson <mark at webb-johnson.net> wrote:
>>>> 
>>>>> Kevin,
>>>>> 
>>>>> How much do you guys pay for the SIM prepaid plans in UK (per month) for OVMS?
>>>>> 
>>>>> Regards, Mark.
>>>>> 
>>>>> On 20 Aug, 2013, at 9:18 PM, Kevin Sharpe ZCW <kevin.sharpe at zerocarbonworld.org> wrote:
>>>>> 
>>>>>> We've seen lots of issues with SIM configuration here and almost ever new OVMS user requires help.
>>>>>> 
>>>>>> When driving I've even lost connectivity in some European countries because I've been unable to remove the SIM for reconfiguration.
>>>>>> 
>>>>>> Anything that simplifies the configuration overhead would be welcome here!
>>>>>> 
>>>>>>      Kevin Sharpe | Founder & Patron
>>>>>> Tel: +44 122 566 7544 ext: 800 | Skype: zerocarbonworld
>>>>>> kevin.sharpe at zerocarbonworld.org | www.zerocarbonworld.org | twitter.com/zerocarbonworld
>>>>>> 
>>>>>> Zero Carbon World is a UK Registered Charity #1141347
>>>>>> From: Mark Webb-Johnson <mark at webb-johnson.net>
>>>>>> Reply-To: OVMS Developers <ovmsdev at lists.teslaclub.hk>
>>>>>> Date: Tuesday, 20 August 2013 15:04
>>>>>> To: OVMS Developers <ovmsdev at lists.teslaclub.hk>
>>>>>> Subject: [Ovmsdev] USSD Signaling
>>>>>> 
>>>>>> 
>>>>>> I've had a proposal from a M2M provider that is interesting, so thought I'd distribute it here, and get feedback.
>>>>>> 
>>>>>> A very low-level protocol in the GSM standard is called USSD. It involves the transmission of a single alpha-numeric message of up to about 120 characters. Our protocol messages would fit perfectly into it. The USSD protocol is routed at a very low level, and is a datagram-syle protocol (it may be discarded by the network if there is no cellular connectivity, kind of like UDP). The protocol is supposedly better able to make it through congested and low-signal areas than even SMS, and certainly much better than GPRS. Message transit times are faster than SMS at around 1 second (of course, depending on cellular coverage).
>>>>>> 
>>>>>> The interesting things about the protocol are than (a) it is free (or flat-rate, at least), and (b) it supports roaming. One SIM, flat rate, globally.
>>>>>> 
>>>>>> The M2M provider suggests that we buy SIMs from them with unlimited USSD plans. Once activated, the SIMs would work globally on hundreds of partner carriers, and would only support USSD (not SMS or GPRS data). The way it would work for OVMS would  be:
>>>>>> 
>>>>>>  • Every OVMS module would be provided with a USSD SIM already onboard. It would work globally.
>>>>>>  • The owner would go to the www.openvehicles.com website and create a vehicle record as normal, but also enter the serial number of the SIM.
>>>>>>  • When the OVMS module powers on, it would read the serial number from the SIM then send a single USSD message to us to request provisioning (vehicleid, server password, etc).
>>>>>>  • The OVMS server would send back a USSD message to provision the module in the car.
>>>>>>  • From then onwards, USSD messages would be used to encapsulate our current OVMS protocol messages.
>>>>>>  • The USSD messages are bi-directionally gatewayed to the OVMS server via the M2M provider, over the Internet.
>>>>>>  • There would need to be some small changes to the encryption protocol we use.
>>>>>>  • The OVMS firmware could support this as a special operation mode - based on the prefix of the SIM inserted. So, it could work in normal SMS/GPRS mode as well as USSD mode (switched by the SIM in the module).
>>>>>> 
>>>>>> Cost wise, this would increase the cost of the module by less than US$10 (price of the SIM). A monthly flat-rate "unlimited" USSD plan would be around US$8-US$10 per month.
>>>>>> 
>>>>>> What do people think?
>>>>>> 
>>>>>> Regards, Mark
>>>>>> 
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