Aperiodic triggering of channel quality information using physical downlink control channel

#The invention relates methods for triggering and reporting on a downlink channel quality (channel quality feedback) experienced by a terminal (e.g. a mobile terminal or a user equipment) by means of channel quality information for at least one of plural component carriers of a communication system available for downlink transmission to the terminal. Furthermore, the invention also relates to an implementation of these methods in hardware and software.

#Long Term Evolution (LTE)

#Third-generation mobile systems (3G) based on WCDMA radio-access technology are being deployed on a broad scale all around the world. A first step in enhancing or evolving this technology entails introducing High-Speed Downlink Packet Access (HSDPA) and an enhanced uplink, also referred to as High Speed Uplink Packet Access (HSUPA), giving a radio-access technology that is highly competitive.

#In the following the invention is described in more detail in reference to the attached figures and drawings. Similar or corresponding details in the figures are marked with the same reference numerals.

#FIG. 1 shows an exemplary architecture of a 3GPP LTE system,

#FIG. 2 shows an exemplary overview of the overall E-UTRAN architecture of LTE,

#The following paragraphs will describe various embodiments of the invention. For exemplary purposes only, most of the embodiments are outlined in relation to an orthogonal single-carrier uplink radio access scheme according to 3GPP LTE (Release 8) and LTE-A (Release 10) mobile communication systems discussed in the Technical Background section above. It should be noted that the invention may be advantageously used for example in connection with a mobile communication system such as 3GPP LTE (Release 8) and LTE-A (Release 10) communication systems previously described, but the invention is not limited to its use in this particular exemplary communication network.

#The explanations given in the Technical Background section above are intended to better understand the mostly 3GPP LTE (Release 8) and LTE-A (Release 10) specific exemplary embodiments described herein and should not be understood as limiting the invention to the described specific implementations of processes and functions in the mobile communication network. Nevertheless, the improvements to the random access procedure proposed herein may be readily applied in the architectures/systems described in the Technical Background section and may in some embodiments of the invention also make use of standard and improved procedures of theses architectures/systems.

#As indicated in the Summary of Invention section, one aspect of this invention is to suggest a new interpretation of a predetermined format for dedicated control information comprising a CQI request flag. The CQI request flag is a flag (e.g. 1 bit) that is used to request a terminal receiving the dedicated control information to provide channel quality feedback. The interpretation of the content of the dedicated control information may or may not depend on the status of the CQI request flag, depending on the implementation. In one exemplary implementation, the predetermined format of the dedicated control information is the “DCI format 0” as defined for 3GPP LTE (Release 8) that is interpreted in a different manner depending on the status of at least the CQI request flag comprised therein. FIG. 4 exemplarily shows the “DCI format 0” as defined for 3GPP LTE (Release 8) for the FDD operation.