TxNextPacketTimer callback was being used for testing only (compliance testing to be precise).
Now there are independent methods and direct calls to automatic timers for the
compliance testing so there is no particular need for this timer anymore.
Application should be able to add some optional callbacks if it needs to.
Ofcourse there is a penalty of 8-12 bytes per callback, but there can be
certain needs of the application that needs to be met for example setting
up a link check request etc.
We have introduced a structure that contains callbacks for the application use.
- 'events' callback is mandatory, user must assign it. Because this callback brings
state changes for the application. We cannot segregate this into individual handlers
because of RAM penalty.
- Other calbacks (none of them are implemented yet are optional).
Example of using the API is provided with doxygen
The EventQueue thread in LoRaMac.cpp is disbanded and the LoRaWAN
protocol is redesigned to store a pointer for an application
provided EventQueue. It means that now the stack runs in the
same thread as application. Application provided EventQueue is used
to defer ISRs from radio driver and timer callbacks as well as the
application events are queued to the same event loop.
The actual mac algorithms are being used as it is in the reference
implementation.
We introduce an internal class that starts a thread and constructs an event queue
to handle deffered calls from interrupt context for RTOS. The code base is
compatible with Mbed-OS 2 as well.
GetPhyEventHandlers() API provides mac callback funtions for PHY layer,
which are in turn delegated to radio driver from the PHY layer.
LoRaMacInitialization() is augmented with LoRaPHY parameter which let's
the MAC layer know which particular PHY layer is in use.
LoRaMacSetTxTimer() and LoRaMacStopTxTimer() are used when duty cycle is
off for testing purpose or to support custom application timers.
If the duty cycle is off, mac and phy layer work togather to figure
out the next possible transmission time.
LoRaMacCrypto APIs are provided which provide seemless integration of
mbedTLS into mac layer for cryptography. User application is supposed to
provide proper mbedTLS configuration file.
All other APIs are retained as it is.
LoRaPHY is the abstract class for the LoRa PHY layer which governs
the LoRaRadio and provides some common functionality to all regional
implementations.
We support 10 regions and every region comes loaded with default parameters.
These parameters can be changed by the Mac layer or explicitely by the stack
controller layer using APIs provided. This layer in essence detaches Mac completely
from PHY and provides more modular approach to the entire system.
Apart from class structure, the internal functionality is directly deduced from
semtech reference implementation that's why most of the internal data structures are
used on 'as is' basis.
In addition to that, the PHY layer provides APIs to control the LoRaRadio layer, i.e.,
the lora radio driver, ensuring that the radio is accessed from a single entry point.
A seperate data structure file is added which is common to PHY layers only.
Hasnain Virk