- Added a bool return status to LoRaPHY::compute_*_win_params(...) methods. Currently, failed status returned if the rx slot type is invalid or rf frequency is invalid
- Updated Class B implementation to check return status
DevTimeAns mac command will carry number of seconds since the GPS epoch
in the first four bytes and the fifth byte is the fractional part.
After extracting the time from the command fields, we need to adjust
this time according to the unix time, so we add the Unix to GPS time
diff to it. After that we account for leap seconds and set the time
using standard set_time() call.
We have removed the method time_received() fom LoRaPHY as it is not
important nor required. It doesn't fit into the LoRaPHY context.
Stubs are therefore updated to reflect the change.
mbed_lib.json now contains the configurable parameters for TAI to UTC
and GPS TAI to UTC differences in seconds needed for leap second
correction. They are loaded with values as of 2018.
Double precision may introduce unwanted results and it's impact is
massive on microcontrollers. So we change the precision from double to
float.
This change doesn't seem to enhance performance yet.
BE to LE fixes, missing MLME types added
LoRaWAN 1.1 Features added (Some LoRaPhy impl missing still + some TODOs in code)
- MLME confirm handling refactored
- Rejoin handling missing
- new CF_LIST mechanism missing (+resets involved)
- NVM handling missing
Rejoin logic added
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'.
While calculating ack timeout, we were ending up getting a random value
which may become less than 2 seconds. This is not allowed as per v1.0.2
specification.
To fix the issue we now take the random number from 0 to 2000 ms and
then add that to the fixed 2000 ms ack timeout value, guaranteeing a
value at least equal to 2000 ms.
In a specific branch path 'adr_settings' in link_adr_request() API, the
structure adr_settings of type link_adr_params_t will be rendered
uninitialized. To prevent this we initialize the construct as zero.
In addition to that, to handle the case properly we should check for the
command identifier and the command payload length anticipating contiguous
blocks of adr commands. If we find a discrepency in size, we should
abort.
Randomizing backoff by 200ms to 1000ms for Join Requests in a dense
network will add robustness and better chances of reception by the base
station especially in cases of catastrophic network outage and
reconnection.
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.
Previously, we weren't filling in RX1 frequecny in rx_window1_config
structure. However, everything worked as in LoRaPHY::rx_config() API
there was a check which filled in correct RX1 frequency.
Now we are filling in RX1 freq. properly while we are computing
parameters for RX1 window.
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.
Previously, we weren't filling in RX1 frequecny in rx_window1_config
structure. However, everything worked as in LoRaPHY::rx_config() API
there was a check which filled in correct RX1 frequency.
Now we are filling in RX1 freq. properly while we are computing
parameters for RX1 window.
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.
- Duty cycle can be now only disabled with duty-cycle-on flag if region supports duty-cycle.
If region does not support duty-cycle, this flag has no effect and duty cycle is always
disabled.
- Also introduced a new flag (duty-cycle-on-join) to disable duty cycle for JOIN requests.
This flag can be used for testing only and is used to speed up JOIN request testing as
backoff times for JOIN request are really long (easily several minutes per attempt).
This flag works in conjunction with main duty cycle setting. Disabling duty-cycle-on-join
works only if duty-cycle-on is disabled (or region settings have duty cycle disabled).
In #b0b0261 we changed the RX2 data rate to start from the highest data rate
available for the PHY rather than standard defined DR.
This introduced a regression, i.e., even when somebody changed the default RX2 data
rate to something usable for their environment, it didn't take any effect. As in
reset_mac_params() we override the data rate with max value possible for that PHY.
This commit restores the original behaviour and we always use standard defined
values.
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.
The stack was trying to connect with default data rates which happened to be
the lowest data rates in a specific region. In the beginning device and NS do
not have agreed upon tx rx parameters and there can be synchronization issues.
When we use lower datarates, we may end up having a minute and a half long
transmissions that hnot only blocks the channel for a long time but also reduce
the chance of proper synch between device and NS. That's why we have decided to
begin with higher data rates and gradually decrease datarate if we do not hear
from the network server.
Instead of giving LoRaWANTimeHandler object as parameter for constructor,
object is now given via own initialize() method.
This change is needed for future refactoring where application can give own
PHY object for LoRa stack.
In rx_config(params) API we shouldn't check for radio state as radio may never get
idle for a class C device. That check made sense only for class A. As the PHY layer
have no conecpt of receive windows which is a MAC layer construct, we should remove the
state check.
The API will be changed later to void rx_config(params).
In addition to that another bug is fixed in the open_rx2_windows() API. We should set the rx slot
first before instantiating a test based on its value.
receive(uint32_t) API in the LoRaRadio class (base class for the radio drivers) should
not take any argument as we decided to take hardware timers for RX timeout interrupts
instead of software timers. It is being refactored to receive(void).
This is an API change, but as it is not an application interface, we will not put a
deprecation notice. Only user of this API is our stack (LoRaPHY layer) which has been updated
accordingly.
Actual driver comes out of the tree and a PR is open there to update the drivers:
https://github.com/ARMmbed/mbed-semtech-lora-rf-drivers/pull/22
In addition to this an internal API belonging to LoRaPHY class is refactored.
set_rx_window(parameters) is refactored to handle_receive(void) which is more consistent with
handle_send().
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.
band_t structure in phy parameters was not being filled in properly
and we were spilling over the array boundary for bands.
In addition to that two utility functions are added to perform safety
checking taking in the frequency and filling out band information plus
boundry value checks.
In LoRa TX power value 0 means the maximum allowed TX power and values >0
are limiting the allowed TX power to lower.
tx_config was incorrectly checking the power level and causing the maximum
TX power to be always used. Lora gateway can request node to use lower TX
power with LinkAdrReq MAC command.
Unknown
Hasnain Virk
Antti Kauppila
Martin Kojtal
Cruz Monrreal II
Kimmo Vaisanen