Measurement-based random access configuration
摘要
說明書
Another embodiment includes application of aspects of the disclosure to an embodiment that involves the legacy initial access procedure with a multi-antenna TP that uses transmit and/or receive beamforming, which was described above. Additional comments regarding the beamforming embodiment with respect to synchronization, measurement RSs and system information, are presented in the following embodiment to which aspects of the present disclosure are applied.
The TP transmits synchronization, measurement RS's and system information. Since synchronization and system information targets all devices (broadcast transmission), the transmission of those signals cannot use only a particular beam, since that would prohibit other devices for which the beam is not suitable, to receive the signals properly. Instead, in various embodiments, transmission without beamforming, e.g. from a single antenna or with a transmit diversity scheme, as in for PBCH in LTE, with more isotropic energy distribution can be used. In some embodiments, the signals can be transmitted on multiple, e.g. all, beams, simultaneously or consecutively in time. In this manner, the likelihood is improved that all devices within the coverage area can receive the signals with sufficient quality. Measurement RSs (such as CSI-RS in LTE) also may target multiple devices. However, it is usually not necessary that all measurement RSs are received with high quality at all those devices of interest. Instead, different measurement RS may be transmitted on different beams. Consequently, some measurement RSs are received with good quality (e.g. high RSRP) at a particular device, while other measurement RSs are received with poor quality (e.g. low RSRP).
