Abstract:
Apparatus and methods are provided for initial access in the multi-beam operation. In one novel aspect, the UE receives multiple response messages and selects one message as the response message. In one embodiment, the UE selects a subset of a configured UL resources, transmits a first message, wherein the first message is transmitted one or more times on each of the selected set of UL resources, receives one or more first-message-response messages from the BS, and selects one response message, wherein the selected response message indicates a corresponding BS RX resource, which is used by the UE for subsequent communication with the BS. In one embodiment, the selection of UL resources is at least based on transmitting spatial characteristics of the BS, the UE or both, which indicates whether the BS/UE is reciprocal, partial reciprocal or non-reciprocal.
Abstract:
A communications apparatus includes a wireless communications module and a controller. The wireless communications module uses a preferred receiving beam determined in a beam training procedure to communicate with a network control device and further monitors one or more candidate receiving beam(s) by using the one or more candidate receiving beam(s) to receive signals from the network control device. The controller calculates a detection metric for the preferred receiving beam and the preferred control beam and a detection metric for each combination of the one or more candidate receiving beam(s) and the preferred control beam, and determines whether to change the preferred receiving beam according to the detection metrics for the preferred receiving beam and the preferred control beam and for each combination of the one or more candidate receiving beam(s) and the preferred control beam.
Abstract:
A method of providing channel station information in a beamforming system is proposed. Reference Signal (RS) is used for channel state estimation. For fine-resolution dedicated beam with smaller spatial coverage, additional channel monitoring of coarse-resolution beams for beam fallback is applied. The joint coverage of monitored fallback beams covers a desired service area. For beam administration, fallback beams need to be evaluated and the most preferable beam is selected for use in case the currently used dedicated beam is no longer suitable. For link adaptation, at least the channel state of the selected fallback beam is evaluated and provided to a scheduler (e.g., a BS) for adapting the transmission of the selected fallback beam.
Abstract:
A method of beam misalignment detection for wireless communication system with beamforming is proposed. To identify a misaligned beam, a relative beam quality degradation is applied by comparing a dedicated beam quality with a reference beam quality. The reference beam favors similar transmission path as the dedicated beam, and has better mobility robustness. In one embodiment, the reference beam is an associated control beam of the dedicated beam. To detect beam misalignment, a first dedicated beam SINR is compared with a second associated control beam SINR.
Abstract:
A method of beam misalignment detection for wireless communication system with beamforming is proposed. To identify a misaligned beam, a relative beam quality degradation is applied by comparing a dedicated beam quality with a reference beam quality. The reference beam favors similar transmission path as the dedicated beam, and has better mobility robustness. In one embodiment, the reference beam is an associated control beam of the dedicated beam. To detect beam misalignment, a first dedicated beam SINR is compared with a second associated control beam SINR.
Abstract:
An incremental scheduling scheme is proposed in a wireless communication system with beamforming. In an initial stage (stage-1), coarse scheduling plan is granted via control beam transmission. In a second stage (stage-2), fine scheduling plan is granted via dedicated beam transmission. Such incremental scheduling scheme provides load balancing for overhead channels on control/dedicated beams via stage-2 scheduling. It utilizes dedicated beam transmission that is more resource efficient and more UE-specific. Furthermore, it provides UE natural power-saving opportunities via stage-1 scheduling.
Abstract:
A method of control signaling in a beamforming system is proposed. A user equipment (UE) receives control beam transmission from a base station using a set of control beams in a beamforming network. Each control beam comprises a set of DL control resource blocks, a set of UL control resource blocks, and an associated set of beamforming weights. The UE selects a control beam for establishing a connection with the base station. The UE then performs random access with the base station using the selected control beam.
Abstract:
A beam indication (BI) mechanism is proposed to provide user equipment (UE) information of network (NW) beam(s) for later transmission. UE can then select its UE beam(s) for the later transmission based on the BI. In one embodiment, NW provides beam management configuration to UE via Radio Resource Control (RRC) signaling, and then provides beam indication index signaling to UE via MAC-CE or DCI. The beam management configuration comprises a mapping table between network beams and configured reference signal (RS) resources. The beam indication index signaling indicates one or more preferred beam pair links (BPLs). Upon triggering a beam management procedure by the network, UE is able to identify the beam management procedure and selects corresponding UE beam(s) based on the beam management configuration and the beam indication index signaling.
Abstract:
A method of beam failure recovery request (BFRQ) transmission is proposed. UE can search for UE-specific control channel in a search space that is signaled specifically for monitoring network response of the BFRQ. Furthermore, configurations indicated specifically for BFRQ can be carried by dedicated signaling such as high-layer radio resource control (RRC) signaling. After successfully rebuilding connection, UE assumes the demodulation reference signal (DMRS) ports of UE-specific control channel to be spatially quasi-co-located (QCL-ed) with the reference signals identified during the beam failure recovery procedure.
Abstract:
A method of beam failure recovery request (BFRQ) transmission is proposed. In a first step of beam failure detection, UE detects a beam failure condition of the original serving beam. In a second step of new candidate beam identification, UE performs measurements for candidate beam selection. In a third step of beam failure recovery request (BFRQ) transmission, UE transmits a BFRQ message to BS upon the triggering condition for BFRQ transmission is satisfied. In a fourth step of monitoring BS response, UE monitors BS response to decide the success or failure of the BFRQ transmission attempt. In one advantageous aspect, the BFRQ transmission is over dedicated contention-free PRACH or PUCCH resources or over contention-based PRACH resources. Furthermore, a beam failure recovery timer is used to oversee the initiation and the termination of the BFRQ transmission.