US902-928 MHz Band

In this section, the regional parameters for the USA, Canada, and all other countries falling within ITU Region 2, which adopt the complete FCC 47 CFR Part 15 regulations within the 902-928 MHz ISM band, are outlined.

Frequency/Channel Plans

The US902-928 MHz band is divided into the following frequency/channel plans as shown in the table below.

Uplink/Downlink Channels Range Frequency range BW Data rate
Uplink 64 0 - 63 902.3 – 914.9 MHz in 200 kHz increments 125 kHz DR0 – DR3
Uplink 8 64 - 71 903.0 – 914.2 MHz in 1.6 MHz increments 500 kHz DR4
Downlink 8 0 - 7 923.3 – 927.5 MHz in 600 kHz increments 500 kHz DR8 - DR13

Data Rates

The following table shows the Bit rate (bit/sec) for each data rate configured with the spreading factor and the bandwidth.

  • DR0 - DR4 and DR8 - DR13 are used for LoRa modulation.
  • DR4 is identical to DR12.
  • DR8 - DR13 are only used for downlink messages.
Data rate Configuration Bit rate (bit/s) Uplink/Downlink
0 LoRa: SF10 / 125 kHz 980 Uplink
1 LoRa: SF9 / 125 kHz 1760 Uplink
2 LoRa: SF8 / 125 kHz 3125 Uplink
3 LoRa: SF7 / 125 kHz 5470 Uplink
4 LoRa: SF8 / 500 kHz 12500 Uplink
5 LR-FHSS CR1/3: 1.523 MHz BW 162 -
6 LR-FHSS CR2/3: 1.523 MHz BW 325 -
7 RFU - -
8 LoRa: SF12 / 500 kHz 980 Downlink
9 LoRa: SF11 / 500 kHz 1760 Downlink
10 LoRa: SF10 / 500 kHz 3900 Downlink
11 LoRa: SF9 / 500 kHz 7000 Downlink
12 LoRa: SF8 / 500 kHz 12500 Downlink
13 LoRa: SF7 / 500 kHz 21900 Downlink
14 RFU - -
15 *Defined in [TS001] - -
Note:
*The DR15 is defined in the LinkADRReq MAC command of the LoRaWAN1.0.4 and subsequent specifications and were previously RFU.

All US902-928 end devices shall support one of the following data rate options.

  • DR0 – DR4 and DR8 – DR13 – the minimal data rate set required to obtain LoRaWAN certification.
  • DR0 – DR13 - all data rates are implemented in the end device

When using Over-The-Air-Activation (OTAA), the end device shall transmit the Join-Request message on a randomly selected channel as follows.

  • 64 channels (each have 125kHz bandwith) defined using DR0
  • 8 channels (each have 500kHz bandwidth) defined using DR4

The end device shall change channels for every transmission.

The maximum radiated output power allowed in the USA is EIRP = +30 dBm but for most devices +20 dBm is sufficient. Under the Federal Communications Commission (FCC) there are no duty cycle limitations but there is a 400 ms maximum dwell time per channel. Dwell time is the amount of time needed for a transmission.

Maximum Payload Size

The maximum MACPayload size (M) and application payload size (N) vary by Data Rate. The maximum application payload size is calculated using M-8 if the FOpts field is absent.

The table below shows both the maximum MACPayload size and the application payload size for each Data Rate, and it is compatible with repeaters.

Data rate Maximum MAC payload size M (bytes) Maximum application payload size N (bytes)
0 19 11
1 61 53
2 133 125
3 230 222
4 230 222
5 58 50
6 133 125
7 Not defined Not defined
8 61 53
9 137 129
10 230 222
11 230 222
12 230 222
13 230 222
14..15 Not defined Not defined

Summary

The following table summarizes all the important parameters we have discussed in this section for US902-928 band.
Default frequency band 902-928 MHz
Mandatory channel frequencies for join-request Upstream: 64 channels - 902.3 – 914.9 MHz in 200 kHz increments
Upstream: 8 channels - 903.0 – 914.2 MHz in 1.6 MHz increments
Downstream: 8 channels - 923.3 – 927.5 MHz in 600 kHz increment
Mandatory data rates for join-request 64 (125 kHz channels) using DR0 and 8 (500 kHz channels) using DR4
Optional data rates 5-6
Number of channels Upstream: 64 (125 kHz) + 8 (500 kHz)
Downstream: 8 (500 kHz)
Default channels Ch0 - Ch71
Duty cycle No limit
Dwell time limitation Ch0-Ch63: 400 ms
Ch64-Ch71: No
Max EIRP (default) - TXPower 0 +30 dBm
Default RX2 data rate DR8
Default RX2 frequency 923.3 MHz