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.
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.
It was decided within the team to retire LoRaWANBase class which served
as a pure virtual interface class from which LoRaWAN network stack
implementations would get inherited. However, the current view is that
we may be the only user of it so we could retire LoRaWANBase.
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 had been incrementing UL frame counter for a CONFIRMED
message only when the transmission was deemed successful i.e., we would
have received an ack before all the retries would have exhausted.
Now we have opted to increment the frame counter if all the retries are
exhausted considering the fact that we essentially treat the next
message after retry exhaustion as a new packet so we should also
increment the frame counter.
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.
The idea behind the method post_process_no_reception() is to post
process any outgoing TX but we shouldn't do that if a CONFIRMED message
is outgoing and there are still some retries left.
After transmission we should change the state before invoking opening of
slots as we may start receiving in the rx slots and the state would
suddenly change from SENDING to RECEIVING without going through the
ACK_WAIT state (in case of CONFIRMED messages). Tests show that after
this slight adjustment, our number of ack retries have significantly
reduced.
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.
Before going after an automatic uplink, we should check if there was an
automatic uplink already ongoing, i.e., the ack for the previous
automatic uplink cycle has not been received.
If there is we shouldn't queue the new automatic uplink and wait for
the previous Ack cycle to complete.
If the packet is already handed over to the PHY layer, we shouldn't be
able to cancel that particular transmission. In addition to that if the
backoff timer is either not applied or has been deactivated, should end
up in no-op rather than having normal termination. A new error code has
been introduced to cover no-op cases. This error code replaces the
compliance test related error code which is no longer relevant.
clear_tx_pipe() does nothing if:
- The stack cannot cancel TX (already handed over to PHY)
- The backoff timer is not active at all
- The event is disaptched to schedule
stop_sending() will only post process ongoin TX if the pipe was
definitely cleared.
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.
The idea behind the method post_process_no_reception() is to post
process any outgoing TX but we shouldn't do that if a CONFIRMED message
is outgoing and there are still some retries left.
Hasnain Virk
Cruz Monrreal
itziar
Martin Kojtal
Ron Eldor
Kevin Bracey
Mel W
Antti Kauppila