We provide now downlink channel frequency and time on air for the
received frame in the RX metadata.
Previously the channel information in both TX and RX metada contained
the index number of the channel. That information wasn't very useful
except the index numbers of default channels. To make more sense of the
meta data, we now store the channel frequency in the channel parameter
rather than the index number of the channel.
RX time on air is collected from the radio driver and it is assumed that
the downlink frame had 8 downlink preamble symbols (plus 4.25 of the
preambles added by the chip) for LoRa modulation.
This commit also include a bit of tidying of RX frequency storage in rx
configuration parameters storage. Previously we were missing filling in
the RX1 frequency correctly.
A bug while setting up RX start timers would result in premature closusre
of RX2 window. The 'ack_Timeout_timer' would be invoked prematurely and
at that time RX2 window may be being demodulating. This resulted in
massive instability with any test that relied on Confirmed traffic or
lower data rates.
To fix the issue, we must know the length of the RX window in
milliseconds and for this purpose we have extended the
'get_rx_window_params(...)' API. The length of the time the window
may remain open must be accounted for while setting up
'ack_timeout_timer'.
Adding group identidier so that LoRaWANInterface class goes to the class
hierarchy section rather than data-structures.
Adding missing documentation for a couple of public functions.
Adding \code and \endcode modifiers for the example code in the
documentation.
Adding compile time NO_DOXYGEN flag for the implementations of the
LoRaPHY Class.
Adding documentation for some of the private structures.
A new algorithm has been taken in use to calculate the receive window
length and the timing offset involved in opening of the said receive
window. This algorithm performs better than the stock algorthm and
consumes less power.
LinkADRReq mac command can be used by the network server to set a
certain level of QOS using NbTrans field which is applicable to
Unconfirmed traffic only for 1.0.2 spec.
This commit introduces mechanisms to facilitate this QOS. It means to
repeat an outgoing unconfirmed message NbTrans times without changing
its frame counter.
For class C, we have retired the ack_expiry_timer_for_class_c and have
replaced it with another timer which mimics the RX2 closure as in Class
A but doesn't actually close RX2 window. It's just a mechanism by which
the state machine is informed that the you can proceed forward, we have
not received anything in RX2 window either. This is needed as RX2
doesn't timeout in class C (i.e., the radio remains in continuous mode).
In addition to that we need to close any pending timers for Receive
windows after the MIC has passed and the Duplicate counter check has
also been passed.
LinkADRReq mac command can be used by the network server to set a
certain level of QOS using NbTrans field which is applicable to
Unconfirmed traffic only for 1.0.2 spec.
This commit introduces mechanisms to facilitate this QOS. It means to
repeat an outgoing unconfirmed message NbTrans times without changing
its frame counter.
For class C, we have retired the ack_expiry_timer_for_class_c and have
replaced it with another timer which mimics the RX2 closure as in Class
A but doesn't actually close RX2 window. It's just a mechanism by which
the state machine is informed that the you can proceed forward, we have
not received anything in RX2 window either. This is needed as RX2
doesn't timeout in class C (i.e., the radio remains in continuous mode).
In addition to that we need to close any pending timers for Receive
windows after the MIC has passed and the Duplicate counter check has
also been passed.
While performing compliance tests with an industry tester, we realized
that there was no need for any extra handling code for the compliance
tests. The tests would run fine, if we only have a handling application.
However, in normal operation we wouldn't like the network to send us any
traffic on compliance testing port. To mitigate that, on the reception
path we filter out any traffic on compliance testing port if compliance
testing is not underway. User should define LORAWAN_COMPLIANCE_TEST macro
in mbed_app.json to enable traffic on compliance test port.
We had a bug especially in the reception path. Our recv window opening
delays were being calculated on the premise that the radio has to capture
5 preamble symbols out of 8 transmitted by the base station. However, in PHY
layer while setting radio rc settings, we were setting preamble length to be 8.
Preamble length register needs to be configured differently for Uplink and Downlink.
For uplink, we wish to transmit 8 preamble symbols whereas in the reception path we need
to receive 5 preamble symbols at least out of 8.
Alongwith that the maximum range of timing error may vary from platform to platform as it
is based upon the crystal in the chip. We have now made these parameters configurable and
have loaded them with the most optimal defaults.
Travis astyle check pointed out some of the style mismatches in the code.
Not all of them are worth changing as they make the code unreadable and
some of them are semantically wrong.
So in this commit, we have attempted to pick the most important style
mismatches and rectify.
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.
While configuring RX parameters for the radio, we need to feed in
rx windows 1 and 2 parameters which are computed when we do the transmission.
We are actually setting the physical value of the data rate rather than
data rate table index and the expectation was to set the data rate index.
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.
Any data structure used in LoRaWANBase class should be available
in a separate header in order to make the code easy to port and
easy to read as the developer doesn't need to know about all the
internal data structures being used in Mbed LoRaWAN stack.
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
Removed the while loop checking the return value from set_next_channel
(GitHub Issue https://github.com/Lora-net/LoRaMac-node/issues/357)
The new return values are:
LORAWAN_STATUS_OK : A channel has been found.
LORAWAN_STATUS_NO_FREE_CHANNEL_FOUND : No free channel has been found (AS923 and KR920 regions)
LORAWAN_STATUS_DUTYCYCLE_RESTRICTED : No channel found due to the duty-cycle or JoinReq back-off restrictions. Trial must be delayed.
LORAWAN_STATUS_NO_CHANNEL_FOUND : No channel has been found. Re-enabled the default channels.
- 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
LoRaMacChannelPlan class provides APIs which are not usable for
PHY layer implementations who do not support custom channel plans.
So we had some code in APIs which was explicitely using magic numbers
for the channel mask. Although it turned out to be not a bug as a layer
down we were checking for custom channel support. However, we now
check for custom channel support before going deep into PHY layer that will
make the code run faster and we have done some cosmetics to the code for
readability.
Channel mask is manipulated with inline methods
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.
Instead of initiating own timer objects we can use EventQueue::call_in() method
as we already have handle to EventQueue object.
Also setting timeout and starting timer has been combined to TimerStart method.
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.
As a part of MAC layer breakdown into independent subsystems, we have
introduced a class for MIB service.
Major changes from the baseline are:
- making OpenRxWindow() public in LoRaMac.cpp
- Moving various data structures to central protocol data structure
MAC layer will services will be broken down into independent
subsystems. This is the first of those efforts. We have introduced
LoRaMacMlme class that handles everything related to MLME subsystem or
subservice. To accomodate subsystems we have grouped all protocol level
variables into one big data structure. A pointer to that data structure
will be passed around the subsystems in order to regulate the entire
system.
LoRaMac::Send() and LoRaMac::SetTxContWave*() APIs are made public as
they are needed to be accessed by the subsystems.
Ticker objects embeded in TimerEvent_t data structure were getting constructed
even for the non LORAWAN builds. And that's what was bloating the builds.
We now lazy initialize them using Mbed-OS utility clas SingletonPtr.
A central data structure has been created that carries all the protocol level
variables for the Mac layer. This is important as we are going to break down
MAC services into subsystems and we will pass around common data using that data structure.
Time handler class had a c style callback attached to it which
had been hampering us to be fully object oriented.
That particular callback is changed to Mbed Callback which is attatched
to a specific object hence allowing us to be fully object oriented.
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.
Hasnain Virk
Antti Kauppila
Martin Kojtal
Cruz Monrreal II
Edd Inglis
Kimmo Vaisanen
Kevin Bracey