"The present document presents a generic description of the hybrid RX-requirements concept for implementation into harmonised standards. The new concept is intended to complement the framework for classical receiver parameters by providing alternative RX parameters that could be used in use cases of radio devices where the classical receiver parameters framework described in ETSI EG 203 336 [i.6]@ clause on RX where alternatives are allowed) cannot be applied@ e.g. if: ? there is no possibility to apply classical receiver parameters and parameters needed for compatibility or sharing studies (e.g. RFID tags and some SRDs); ? classical receiver parameters do not fulfil the requirements for describing the performance of the receiver (e.g. UWB@ radio-determination@ and inductive systems). The present document will evaluate the relationship of the new concept with the classical RX- parameter framework@ such as blocking@ sensitivity and adjacent channel selectivity. The present document presents exemplary use cases and extracts related RX parameter to describe a harmonised extension of the existing RX parameter framework. The STF will ensure that the conclusions of its work should be included in harmonised standards in the following ways: ? It will provide a way to define clear limits that are objective@ measurable and repeatable. ? It should ensure that a receiver to which the defined limits are applied has a level of performance that allows it to operate as intended and protects it against potential harmful interference. ? It will not define specific values for limits or device-related requirements but focus on the procedure and definitions of appropriate receiver parameters. The present document is the first deliverable of STF 541 and it will be followed by an ETSI Technical Specification. The present document provides an overview of the situation regarding receiver requirements including the definitions@ required parameters (e.g. interfering signals definition). The later TS will provide conformance test procedures for the different use-cases/scenarios. The TS is intended to be used as a normative reference in ETSI harmonised standards which have ""signal interferer handling"" as an essential RX-requirement. During the proposed action@ a set of evaluation measurements will be performed applying the new concept@ and the feedback collected will be included in the final definition of the test and measurement procedures. The output of the STF could be suitable for incorporation into a revision of the ETSI Guide (ETSI EG 203 336 [i.6]) to Harmonised Standards under the RED."