Ich hab nochmal recherchiert, massgebend ist das Dokument =>
ETSI EN 300 220-1 V3.1.1 (2017-02)
Short Range Devices (SRD) operating
in the frequency range 25 MHz to 1 000 MHz;
Part 1: Technical characteristics and
methods of measurement
Darin findet sich unter "5.21 Polite spectrum access", welches praktisch LBT ist, allerdings ist das nach meinem Verständnis nicht zwingend vorgeschrieben:
5.21 Polite spectrum access
5.21.1 Description
Before transmitting, a polite device senses the channel for at least the Clear Channel Assessment interval to determine if
it is free. If the average signal level over the clear channel assessment listening interval is below the CCA threshold the
device proceeds with the transmission.
If the average signal level is above the signal threshold, the polite device defers its transmission to a later time. The
equipment shall not attempt re-transmission on the same operating frequency until a random interval has expired
(multiple of the minimum deferral period). Alternatively, the equipment may select another operating frequency and
again start the listen time before Transmission (AFA as described in clause 5.21.4).
A polite spectrum access can be used with channel adaptivity in case the RF channel is not available.
ERGÄNZUNG:
Muss mich verbessern, und zwar entsprechend folgendem Dokument =>
ETSI EN 300 220-2 V3.1.1 (2016-11)
Short Range Devices (SRD) operating
in the frequency range 25 MHz to 1 000 MHz;
Part 2: Harmonised Standard covering the essential
requirements of article 3.2 of Directive 2014/53/EU
for non specific radio equipment
und darin heisst es dann =>
4.5 Polite spectrum access conformance requirement
4.5.1 Description
For the purpose of the present document, the description in ETSI EN 300 220-1 [1], clause 5.21.1 applies.
Heisst dann also doch nichts anderes, als dass wohl LBT auch hier vorgeschrieben ist.