rx_abort() was sort of dead code as it was doing essentially nothing.
It might have actually meddled with the state machine if it was hit by
invoking on_ack_timeout_timer_event().
State machine and corresponding processors now take care of the ack timeout,
retries and all other bits, so we don't need abort_rx().
MCPS confirmation should be filled with the current number of retries
if the ack is not recieved for a CONFIRMED message.
Ack retry number needs to be incremented after the retry is made not before
that.
A few traces are added at the crucial junctions of the code just to tally with
the conceptual flow for debug purposes.
Application can use cancel_sending() API to stop any outstanding, outgoing
transmission (a TX which is not already queued for transmission). This can
potentially enable use cases where the application could cancel a transmission
and go to sleep if the backoff period is long enough rather than waiting for
the transmission to happen.
This API enables the application to get hold of remaining time after which
the transmission will take place. User can query the backoff time whenever
there is a packet in the TX pipe. If the event for the backoff expiry is
already queued, the stack does not provide backoff metadata.
An API is added to fetch any meta-data available after a succesful
transmission. The stack will make the meta data available after the
TX interrupt is processed. User can get the tx meta data after receiving
TX_DONE event.
In the reception data path, we needed to check the MCPS CONFIRMATION type
not the MCPS INDICATION type. Indication message type is for downlink message type
which can be UNCONFIRMED even if we have sent a CONFIRMED one, e.g., an ACK.
Application can give battery_level callback method what Lora stack
uses to query battery level for DevStatusReq MAC command response.
The problem was that this callback was never called.
This commit fixes this problem and if application does not set
battery_level callback at all, value 255 (= The end-device was not able to
measure the battery level.) will be returned to lora gateway.
There had been essentially two state machines running in our stack
which was too cumbersome and was not alligned in any symmetry.
In this work we make sure that:
* There are no callbacks from the MAC layer to Stack controller layer.
* Primitives are made local to the mac layer and are presented as
read-only to the stack controller layer.
* Interrupt handling and processing is moved to the stack controller layer.
* Reception is divided into smaller units, seperating handling of Join Accept
and normal data frames. MIC gets its own unit.
* Extraction of data and MAC commands from the payload is also being done now in
its own method.
* To ensure integrity of the stack, and sanctity of the radio payload, we copy the
radio payload buffer immediately in the rx interrupt and hoist a flag that prevents
another interrupt from happening for a short while when we are processing the previous
packet.
* If an automatic uplink is on going, we do not send a TX_DONE event to application
anymore as that is logically incorrect.
* state_controller() is the central engine for the state machine. To save code space and
memory, we are not handling each and every state in the state_controller(). Some of the states
which have no processing to be done, are explicitely set.
* For all the states who need special processing, seperate methods are added.
* Class A always run to completion to IDLE and CLass C always runs to completion as RECEIVING.
Currently lora stack will automatically send an empty uplink message to lora gateway in case of:
- Node received message with pending bit set.
- Node received MAC command which requires instant response (sticky MAC command)
- Node received confirmed message in class C mode
This commit makes this configurable via config item
"automatic-uplink-message": {
"help": "In case of pending bit, class c confirmed message or sticky MAC command, stack will automatically send empty uplink message",
"value": true
}
Default value is true. If sending an empty message fails, stack will send event AUTOMATIC_UPLINK_ERROR application.
If automatic uplink sending is disabled, stack will send application UPLINK_REQUIRED -event to indicate
application should issue a new uplink to gateway as soon as possible.
This is a fix for issue #6389.
Currently when application receives RX_DONE event from stack, it has to provide the correct port
value to receive method in order to read the received message. The problem is that current
API does not provide any way to know in to which port message was received.
This commit introduces a new receive() method, which instead of checking these values, will return
them to application.
Fix compilation of compilance test and at the same time refactor compliance
test handler. Renamed mcps_request as test_request as it is only used for
compliance test. Also fixed a bug with null buffer in send_compliance_test_frame_to_mac.
- This is internal change, no functionality has been changed
- LoRaWanInterface cleaned up and code moved to LoRaMacStack
- Compliance code in LoRaMacStack moved to EOF
- Green tea tests have been run manually
- Doxygen updated accordingly
LoRA: reorder class members
This API can be used to runtime change device class.
Please note that only class A and C are supported at the moment.
Trying to set class B will return LORAWAN_STATUS_UNSUPPORTED.
Fix set_device_class documentation
fix documentation
- Internal changes only
- reset function is created to LoRaPHY to reset LoRaMAC parameters with default values
- Doxygen updates for newly created functions
- This is internal logic only and there are no functionality changes
- Some compliance test stuff have been moved to end of files
- Some internal data structures removed as useless after refactor
- get_phy_params function was very heavy weight and needed to be refactored.
- switch-case clauses have been refactored to be functions now and the complexity of the usage has been improved a lot.
- There are no functional changes, this is internal only change
The PHY layer had a lot of duplicated code in various geographic regions.
In this commit we have tried to concentrate all common functionaliy into
one single class which LoRaPHY that provides three kind of methods:
i) Non virtual base methods which are there for upper layer use, e.g.,
providing access to driver or generic PHY layer functionality which
needs to be exposed to upper layers.
ii) Virtual methods (no hard limit on implementation) that can be overriden
in derived classes. Some PHY implementations will need that as they may
come with very peculiar channel schemes, e.g., dynamic channel schemes
in US bands.
iii) Protected methods which are only available for the derived PHYs
We have adopted a mechanism for the dervied PHYs to announce their differenmtiating
parameters in their constructors by filling up a data structure known as lora_phy_params_t
which exists at base level. Access modifier for this data structure is protected so it can only be
used by the base or derived classes, i.e., no exposure to upper layers.
For extra functionality and differentiating controls, a derived PHY can override any virual method as necessary.
In addition to that we have adopted the Mbed-OS style guide and have changed data structures and code to reflect that.
Some data structures are removed.
* Algorithm to get alternate DR is modified. Current scheme, works as multiples of 6 as EU and EU like PHYs
provide 6 datarates. We make sure that we try a datarate at least once. If nuber of join retries is a multiple
of 6, we may try multiple times on each data rate.
* Most of the PHYs with dynamic channel plans, always override the above mentioned algorithm as the rules governing
this algorithm do not hild in their case.
* band_t data structure is enhanced with lower band frequency and higher band frequency. That enables us to validate
frequency based upon the band and hence we can have a single function for all PHYs to validate frequency.
* In some PHYs, there were some extra channel masks were defined which were not being used. Hence removed.
* EIRP table corrected in some PHYs based upon spec.
* PHY functions in response to Mac commands are renamed to reflect what they exactly do.
for example accept_rx_param_setup_req() because that's what they do. they can either accept
the mac command or reject it.# Please enter the commit message for your changes.
This commit also introduces API change for disconnect(). disconnect() will
now return LORAWAN_STATUS_DEVICE_OFF for successfull disconnect.
* LoRaWANStack::handle_tx() can be called with NULL buffer when length is 0.
This commit fixes the case where user has provided NULL buffer and length
is > max_possible_size.
handle_tx() now always returns LORAWAN_STATUS_PARAMETER_INVALID if given
buffer is NULL pointer and length > 0.
General error checking is added and some asserts are added for events.
In order to reset LoRaMac's state in disconnect, we need to implement
an API which can be used to cancel all outstanding requests and reset
LoRaMac's internal state to idle.
This commit introduces LoRaMac::disconnect() which can be used for
this purpose.
We now save roughly 500 bytes by removing storage of default
parameters in the loramac_params_t data structure. We use Mib to
get default values from PHY whenever needed instead.
loramac_sys_arams_t now contains only the runtime values set during operation
whenever defaults are needed we directly query the PHY layer or via Mib as the
need maybe.
Baseline is changed to use a single set of data structures that simplifies the
code in the LoRaWANStack and Mac layer. We are now following certian rules for naming
data structures.
- All structures visible outside their domain are prefixed as 'lorawan_'
- All mac structures are prefixed as 'loramac_'
- All subsystem or module strucutures carry their name in prefix, like 'mcps_'
PHY layer still have legacy camel case data structures which will be entertained
later while we will be simplifying PHY layer.
Test cases are also updated with the new data structure naming conventions.
One major difference from the previous baseline is the removal of static buffer
from mcps indication. And we do not copy data from stack buffer to rx_msg buffer.
This saves at least 512 bytes.
It may look like now that if we have received something but the user have not read
from the buffer, then the buffer will be overwritten and we will lose previous frame.
Yes, we will. But the same will happen even if we would have copied the buffer into rx_msg
because then the rx_msg gets overwritten. So we decide to abandon copying the buffer at
multiple locations. We inform the user about reception, if the user doesn't read and
the data gets overwritten, then so be it.
Channel planning was distributed over LoRaWANStack and LoRaMac previously.
We now centralize it by allocating the service to its own class.
Thus making the workflow consistent, i.e.,
Request for channel plan = Application->Interface->stack->Mac->ChannelPlan
Major change apart from adding the channel plan subsystem are the API changes
in LoRaMac class.
LoRaWANTimer is now called as LoRaWANTimeHandler class as this class handles both
current time and timer functionalities.
Some refactoring on how LoRa objects are created was needed:
- LoRaWANTimeHandler object is created by LoRaWANStack and shares with LoRaMac and PHY.
- LoRaPHY object is now member of LoRaWANStack class instead of static variable in source file.
MAC layer is now a class rather than being a blob.
In addition to that Mac commands are now being handled in
a seperate subsystem (a class of its own). In future we
will do the same with othe sublayers of MAC like MLME, MCPS etc.
The drive behind this exercise is to make MAC and supporting layers
into an object oriented system.
Major bug fixes include:
- last join time inclusion in band parameters
- disabling rx2 window if we missed the slot already
- MLME uplink schdule hook
- nbRep according to spec
- maintaining datarate after successful joining
- suppressing MLME requests if MAC is in TX_DELAYED state
- Uplink dwell time verification
Some missing features are implemented. Details are as follows.
Support for LinkCheckRequet:
An application API is added, add_link_check_request() to delegate a
request for Link Check Request MAC command.
* Application provides a callback function that needs to be called on reception of
link check response.
* Mac command is piggybacked with data frames.
This API makes the sticky MAC command stick with the application payloads until/unless
the application un-sticks the said mac command using remove_link_check_request() API.
Handling fPending bit:
If in the Downlink, we get the fPending bit set in fctrl octet,
we attempt to send an empty message back to Network Server to
open additional Receive windows. This operation is independent
of the application. An RX_DONE event is queued bedore generating
the said empty message. Specification does not mention what can be the
type of that empty message. We have decided it to be of CONFIRMED
type as it gives us an added benefit of retries if the corresponding
RX slots are missed.
Radio event callbacks as Mbed callbacks:
radio_events_t structure has been carrying C-style callbacks which was
inherited from the legacy code. These callbacks has now been changed to
Mbed Callbacks that makes sure that we can be object oriented from now
on.
Setting up user defined data rate was found broken maybe because of
some rebase issue. Code has been setting always the default data rate
and ignoring used defined values.
We had a lot of static objects which would get constructed and hence
pull in some of the LoRaWAN code into the builds for other technologies.
Such objects have been now lazily initialized using utility class
SingletonPtr.
Current implementation uses high resolution timers to calculate elapsed time.
This prevents for example deep sleep completely and causes unnecessary timer
events.
This commit changes implamentation to use EventQueue::tick() to get elapsed time.
All compliance test related codes are now inside LORAWAN_COMPLIANCE_TEST
build flag. This will reduce memory usage in when compliance test codes
are not needed.
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
Receive API should return the length of data written to the user buffer
as the Posix APIs suggest rather than sending the pending length of data
back.
That has actually been a typo mistake which actually wnt in even with doicumentation :)
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.
LoRaWANStack class is our controller layer on top of our
current MAC and PHY layer. It provides services to an implementation
of LoRaWANBase class.
It is a singleton class owing to the fact that the mac layer underneath
is not a class object. Instead, it uses the MAC via setting mib, mlme, mcps
requests and getting responses back from the mac layer using confirmations and
indications.
In essense this class is a special handle for
mac layer underneath which is predominantly reference design based.
In future we may refactor the LoRaMac.cpp code to make it object oriented
and cleaner.
At one end, it binds the application selected radio driver with the PHY layer
and at the other end it provides services to upper layers handling the mac via
well defined APIs.
For proper selection of a PHY layer, user must use Mbed config system.
For this purpose an mbed_lib.json is provided which can be overriden by the
user defined mbed_app.json. By default the EU868 band is selected as a PHY layer.
User must set relevant keys for the selected connection mechanism.
Hasnain Virk
Cruz Monrreal
Kimmo Vaisanen
Antti Kauppila