Data Sheet

14
Version 1.1
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9.0 Programming the device
Refer to WiPy3, Gpy or LoPy module users manual
11.2 Reception Paths Characteristics
The SX1308/ SX1301 digital baseband chip contains
10 programmable reception paths. Those paths
have differentiated levels of programmability and
allow different use cases. It is important to
understand the differences between those
demodulation paths to make the best possible use
from the system.
IF8 LoRa Channel
This channel can be connected to Radio A or B
using any arbitrary intermediate frequency within
the allowed range. This channel is LoRa only. The
demodulation bandwidth can be configured to be
125, 250 or 500 kHz. The data rate can be
configured to any of the LoRa available data rates
(SF7 to SF12) but, as opposed to IF0 to 7, ONLY the
configured data rate will be demodu -lated. This
channel is intended to serve as a high speed
backhaul link to other gateways or infrastructure
equipment. This demodulation path is compatible
with the signal transmitted by the SX1272 & SX1276
chip family.
IF9 (G)FSK Channel
Same as previous except that this channel is
connected to a GFSK demodulator. The channel
bandwidth and bitrate can be adjusted. This
demodulator offers a very high level of
configurability, going well beyond the scope of
this document. The demodulator characteristics
are essentially the same than the GFSK
demodulator implemented on the SX1232 and
SX1272 Semtech chips.
This demodulation path can demodulate any
legacy FSK or GFSK formatted signal.
IF0 to IF7 LoRa Channels
Those channels can be connected individually to
Radio A or B. The channel bandwidth is 125 kHz
and cannot be modified or configured. Each
channel IF frequency can be individually
configured. On each of those channels any data
rate can be received without prior configuration.
Several packet using different data rates may be
demodulated simultaneously even on the same
channel. Those channels are intended to be used
for a massive asynchronous star network of
10000’s of sensor nodes. Each sensor may use a
random channel (amongst IF0 to 7) and a different
data rate for any transmission. Typically sensor
located near the gateway will use the highest
possible data rate in the fixed 125kHz channel
bandwidth (e.g. 6 kbit/s) while sensors located far
away will use a lower data rate down to 300 bit/s
(minimum LoRa data rate in a 125 kHz channel).
The SX1308/ SX1301 digital baseband chip scans
the 8 channels (IF0 to IF7) for preambles of all data
rates at all times. The chip is able to demodulate
simultaneously up to 8 packets. Any combination
of up to 8 packets is possible (e.g. one SF7 packet
on IF0, one SF12 packet on IF7 and one SF9 packet
on IF1 simultaneously). The SX1308/ SX1301 can
detect simultaneously preambles corresponding
to all data rates on all IF0 to IF7 channels. However
it cannot demodulate more than 8 packets
simultaneously.This is because the SX1308/ SX1301
architecture separates the preamble detection
and acquisition task from the demodulation
process. The number of simultaneous
demodulation (in this case 8) is an arbitrary system
parameter and may be set to any value for a
customer specific circuit.
The unique multi data-rate multi-channel
demodulation capacity of channels 0 to 7 allow
innovative
network architecture to be implemented:
- End-point nodes can change frequency with each
transmission in a random pattern. This provides vast
improvement of the system in term of interferer
robustness and radio channel diversity
- End-point nodes can dynamically perform link rate
adaptation based on their link margin without adding to
the protocol complexity. There is no need to maintain a
table of which end point uses which data rate, because all
data rates are demodulated in parallel.
- True antenna diversity can be achieved on the gateway
side. Allows better performance for mobile nodes in
difficult
multi-path environments.
Packet Engine and Data Buffers
10.0 Power
AVG (no radio) 45mA
AVG (TTN gateway) 565mA
MIN (TTN gateway) 220mA
MAX (TTN gateway) 750mA
11.0 LoRa
11.1 Supported features Table 15 - J2 Battery connector pins