Indy RS2000, RS1000, and RS500 module support for the ETSI Upper Frequency Band

The Impinj Indy RS2000, RS1000, and RS500 RAIN reader modules are able to take advantage of the new ETSI (European) frequency band (CEPT REC 70 03 / EN 302 208). The new features in this band include:

  • Doubling the maximum radiated power output to 4W ERP (from 2W ERP). This improves the link budget, most notably providing greater read range (distance between the reader antenna and tag).
  • A frequency band common with FCC in North America, allowing for simplified global deployments that share the same tags.
  • Faster communication between reader antenna and tag for improved tracking of moving items.

This article covers topics you will want to know when designing an embedded reader system to support the new upper frequency band using the Indy reader modules.

Disclaimer: Local regulations must be consulted to ensure regulatory compliance. Not all countries that permit EU Lower Band also permit EU Upper Band. In some cases, EU Upper Band is permitted but not at the higher transmit power (e.g. Russia).

ETSI Upper Frequency Band

The ETSI Upper frequency band has 3 channels, compared to 4 in the lower band. The radiated power is also doubled, to 4 watts ERP.

Standard Channel Center Frequency
(MHz)
Channel Spacing
(kHz)
Channel Bandwidth
(kHz)
Maximum Radiated Power (Watts ERP)
ETSI Lower Band 865.7, 866.3, 866.9, 867.5 600 200 2
ETSI Upper Band 916.3, 917.5, 918.7 1200 400 4

Hardware SKU Frequency Support

Any of the Indy module SKUs which support FCC operation will also support the new ETSI upper band. This includes RS2000-1 and RS2000-2, RS1000-1, and RS500-GX.

RFID reader antennas are often designed for a specific frequency band, optimizing gain and reflection loss for that frequency range. Existing ETSI lower band antennas should be re-evaluated and potentially modified or replaced for operation in the upper band.

Any hardware change to a RAIN reader will require re-certification with regulatory bodies such as the FCC and ETSI.

Hardware Transmit Power Support

The Indy reader modules each have transmit power capabilities that are unchanged by the introduction of the new ETSI upper frequency band. The modules cannot transmit above their maximum transmit power levels, and thus in certain antenna configurations, will not be able transmit at the new 4W ERP allowed maximum. Reader module transmit power maxima are shown in the table below. Reader module transmit power is configured using the ANTENNA_TX_POWER key.

Indy Module RS500 RS1000 RS2000  
Max Tx Power 23 27 31.5 dBm

Software/Firmware Configuration

Indy modules' frequency hopping behaviors are governed by the configurable regulatory regions.The module firmwares contain pre-configured regulatory regions, but custom regions can also be loaded to support regions that were not included in the firmware loaded on the modules. This functionality is documented in the custom regulatory region configuration example in the ITK-C documentation. Example code for an ETSI upper frequency band configuration is shown below. This code for step 1 should replace the code for step 1 shown in the FCC custom region configuration at the location linked above.

IRI ETSI Upper Band Custom Region Configuration Code Snippet

/*
* 1. Setup ETSI Upper Frequency Band Custom Region
*/
key_value_count = 9;

memset(key_value, 0, sizeof(key_value));
memset(&key_list, 0, sizeof(key_list));

key_value[0].key = E_IPJ_KEY_REGION_ON_TIME_NOMINAL;
key_value[0].value = 400;
key_value[1].key = E_IPJ_KEY_REGION_ON_TIME_ACCESS;
key_value[1].value = 400;
key_value[2].key = E_IPJ_KEY_REGION_OFF_TIME;
key_value[2].value = 0;
key_value[3].key = E_IPJ_KEY_REGION_OFF_TIME_SAME_CHANNEL;
key_value[3].value = 0;
key_value[4].key = E_IPJ_KEY_REGION_START_FREQUENCY_KHZ;
key_value[4].value = 916300;
key_value[5].key = E_IPJ_KEY_REGION_CHANNEL_SPACING_KHZ;
key_value[5].value = 1200;
key_value[6].key = E_IPJ_KEY_REGION_RANDOM_HOP;
key_value[6].value = 1;
key_value[7].key = E_IPJ_KEY_REGION_INDY_PLL_R_DIVIDER;
key_value[7].value = 60;
key_value[8].key = E_IPJ_KEY_REGION_RF_FILTER;
key_value[8].value = 0;
error = ipj_bulk_set(iri_device, &key_value[0], key_value_count, NULL, 0);
if (error)
{
printf("ERROR: IPJ_BULK_SET FAILED - ERROR CODE: %d\n\n", error);
return error;
}

The wider bandwidth of the ETSI upper frequency band also allows use of more aggressive link profiles. For example, Profile 3, the "very fast" profile which uses a 400 kHz FM0 backscatter link, which can be configured using the firmware key E_IPJ_KEY_RF_MODE.

Achieving a higher transmit power output to reach 4 watts ERP will require modifications to the configured transmit power of the reader, which is controlled by key E_IPJ_KEY_ANTENNA_TX_POWER.

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