I know How to send a message for car a to car b or rsu. but I need to send beacons. what is different between sending a message and sending beacons. I cant see any sendBeacon(). How should I send one?
Fundamentally, a beacon is simply a repeated broadcast message that carries some information of general interest in the vicinity of the sender. You can achieve this in Veins by having your application call its sendDown method every once in a while.
You can find some example code that does this in https://github.com/sommer/veins/blob/veins-4.5/src/veins/modules/application/ieee80211p/BaseWaveApplLayer.cc#L242
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I have several ECAN within the PIC18 and PIC24 (on OpenCan) with Can Transceiver attached to the CAN Bus network. In event one module send a message and received by other modules (within ECAN), will all ECAN do CRC check and if passed, make dominate bit or just one one of many make this response?. In other words, does PIC ECAN make ACK response even the message is not assigned for that module?
CAN controllers generate dominant ACK bits if they receive the frame without any errors. ID filtering takes place after that. So yes, the CAN controller generates ACK even for the frames it's not interested in.
If a transmitter detects dominant ACK bit, it concludes that at least one node in the bus has received the frame correctly. However, it's not possible to determine if this receiver was the intended one.
As far as I understand, ACK bit makes it possible for a transmitter to self-check. A transmitter can think "If no one hears my message, then I should be the one having problems." if it samples recessive ACK bits. The reception of the message by the intended node should be checked by higher layer protocols, like CANopen.
Transmitter node transmits CAN MSG and monitors the bus for a dominant bit in the ack. slot. Receiver if receives the message correctly, will overwrite the ack. bit and make it dominant. If it does not receive the message correctly, it will not overwrite the ack. slot. Then the transmitter knows that one node has not received the message correctly because it will detect a dominant bit written by the other nodes and assume that all the nodes have received the correct message. Even if one node does not receive the data correctly the message is retransmitted by the transmitter.
Check if you can successfully transmit CAN messages. The problem you could have is in receiving messages. When you send a message to PIC, the message is not received. The message received flag is never set. You have to check that a message is being sent with the scope, check if your PIC stores it. Check which mode is it in, I assume 0, and if it is configured to receive all messages, even with errors.
Check on the scope if the PIC sends and receives the Ack response. When a message is then transmitted back to the pic, check if it sends an Ack response or receives the message!
CAN is a broadcast network so a node does not really know how many other nodes share the bus with it.
With that manner, all the nodes shall do the CRC check and ACK whether the messages are "assigned" (supposed to be received in application layer) by the listened node or not.
There are no conflict, since if there a error with CRC or ACK, all listened nodes shall send (active or passive) Error Frame which are same form from every nodes.
I recommend you to refer this excellent article:
http://www.copperhilltechnologies.com/can-bus-guide-error-flag/
I need to send a message only to one vehicle that i want to choose. I am reading the available TraCIDemo11p and the cars are broadcasting the message to all cars. How can change that and make it send the message to only one care for example to car number 3.Thank you
Keep in mind that communication between cars in Veins (or any MANET simulator) is wireless which means that many cars can hear the MAC frame that sent to a specific node.
To send a message from car A to another car B, they must be in their wireless range or they support an ad-hoc routing protocol to reach other not-in-range cars (which is not implemented in Veins, AFAIK).
If you are sure that both sending and receiving cars are in range, then you can fill the destination address in WSM by the ID of the intended car and let the WAVE application to delete any message that has a destination address different from the local ID.
I use Twilio with my team management system. A text message is automatically sent out for each game. The receiver can then reply with YES or NO. My issue is that when I send two text messages, I have no way to tell if the reply is for the first message I sent, or the second.
Does Twilio have any way to determine which text message it was a response to?
Twilio developer evangelist here.
If you are sending two messages from one Twilio number to the same user number there is nothing within the SMS specification that allows a user to reply to a specific message, so there is nothing you can do with Twilio to detect that.
If you are sending two messages to two different numbers and you get replies from those numbers, you can match against the from number and see what the last message sent from that number was and attach the reply to that.
Alternatively, if you want to get replies from one user to different messages, you could send them from different Twilio numbers. That way you can match the outgoing number to the message and the answer. This is mostly used for phone number masking to enable anonymous communications and there is a good tutorial available on this in the Twilio documentation.
Let me know if that helps at all.
As I know concatenated sms are split in GSM handset and delivered to network. Does GSM standard talk about order of these packets? Will it be always sent in order? That is first sequence packet first and next later?
My questions regarding this.
1. Does SMPP talk about order of long sms segments? Like is it possible for SP to get out of order messages?
2. Does GSM handset deliver long messages always in order or not?
"long sms" officially known as concatenated sms can and will turn up in any order. Therefore the receiving device / system must be able to cater for this. Concatenated sms come in the form of multiple sms. Encoded within is the part number and the total number of parts for the concatenated sms (you can search for information on the "UDH - User Data Header" to get more information).
So answering your questions:
1) There is no ordering in the sending / receiving of concatenated sms. Only information within each concatenated sms part which says which part it is and how big the complete concatenated sms is.
2) GSM handsets tend to send out in order. The order is lost usually during the store and forward process on the SMSC side. On a side note GSM handsets when receiving a concatenated sms build the sms once all parts are received.
I have noticed that certain SMS messages that I receive from companies come with a 'sender name'. eg. Just today I received an SMS from a number I have never used before (not im my contacts), however the senders name showed up as 'Adobe'. I get this from other companies too. eg Facebook, Google & Banking.
Is it similar to how a email server works? (you tell the server who you 'are' before you send the message) Is this the case with a carrier's cell tower?
I guess I'm wondering what the service is called and how it works? (ie. can you send 'header info' with SMS messages or is the cell tower just spoofing the message's 'sender number' and replacing it with characters?)
(hopefully this is the right place to ask this question...)
The MAP protocol (the one used for sending SMS messages among others) allow specifying either a phone number or an alphanumeric number as the sender.
AFAIK this cannot be set from your phone where the sender number will be always your public phone number but SMS Centers can allow sending such messages on other interfaces like the ones used by banks and the companies mentioned by you (usually using the SMPP or UCP protocoll).
Please note that some Telcos do not allow this kind of sender address in messages originated elsewhere but sent to their customers (or they don't allow it for everybody). They use SMS spam filters/firewalls called Home Routers for this.
Mobile communication in GSM, UMTS and LTE is governed by 3GPP.
The TP-OA field in SMS-DELIVER TPDU in an incoming SMS typically contains the number of a sender.
The network fills the TP-OA field with usually an MSISDN.
Please see 3GPP TS 23.040 Figure C.10.
But in case of a company name, TP-OA can be made alphanumeric using the Type of Number Information Element as 7-bit default alphabet
I suggest you to read 3GPP TS 24.011 and 23.040 to get an idea of how SMSes work.
However, I must point out that since a sender does not send TP-OA, it can't be easily spoofed.