Qualcomm noted that further enhanced massive MIMO was one of the key areas of improvement in Rel-17
According to a report by Ericsson, Rel-17 MIMO enhancements address four areas: Beam management; multiple transmission and reception points (mTRP) for ultra-reliable, low-latency communication (URLLC); mTRP for enhanced mobile broadband (eMBB); and TDD and FDD reciprocity.
“The multi-beam enhancements are intended to improve performance at high mobility by streamlining signaling and to optimize performance for user equipment (UE) with multiple antenna panels. The mTRP enhancements increase robustness for the physical downlink control channel (PDCCH), physical uplink shared channel (PUSCH) and physical uplink control channel (PUCCH),” Ericsson said. “They also enable richer channel state information (CSI) feedback for non-coherent joint transmission (NC-JT) and optimize performance for high-speed-train (HST) communication scenarios.
“Finally, the enhancements to reciprocity-based operation include new codebooks with reduced feedback overhead, where partial channel knowledge is available at gNodeB (gNB), as well as improvements to the Sounding Reference Signals (SRSs),” the vendor added.
3GPP noted that the Rel-15 NR includes a number of MIMO features that facilitate utilization of a large number of antenna elements at the base station for both sub-6GHz and over-6 GHz frequency bands. “The Rel-16 NR enhances Rel-15 by introducing enhanced Type II codebook with DFT-based compression, support for multi-TRP transmission especially for eMBB and PDSCH, enhancements for multi-beam operation including reduction in latency and/or overhead for various reconfigurations (QCL-related, measurements), SCell beam failure recovery (BFR), and L1-SINR. In addition, low PAPR reference signals and features enabling uplink full-power transmission are also introduced,” 3GPP said.
“As NR is in the process of commercialization, various aspects that require further enhancements can be identified from real deployment scenarios. Such aspects include the following. First, while Rel-16 manages to offer some reduction in overhead and/or latency, high-speed vehicular scenarios (e.g. a UE traveling at high speed on highways) at FR2 require more aggressive reduction in latency and overhead – not only for intra-cell, but also for L1/L2 centric inter-cell mobility. This also includes reducing the occurrence of beam failure events.” “Second, while enhancements for enabling panel-specific UL beam selection was investigated in Rel-16, there was not sufficient time to complete the work. This offers some potential for increasing UL coverage including, e.g. mitigating the UL coverage loss due to meeting the MPE (maximum permissible exposure) regulation. It is noted that MPE issue may occur on all transmit beams from the panel, therefore, a solution for MPE mitigation may only be performed per panel basis to meet the regulatory requirement for scenarios of interest,” 3GPP said.
3GPP also said that some of the objectives of the work item dubbed ‘further enhancements on MIMO for NR’ are as follows:
-Extend specification support in the following areas [RAN1]
1. Enhancement on multi-beam operation, mainly targeting FR2 while also applicable to FR1:
2. Enhancement on the support for multi-TRP deployment, targeting both FR1 and FR2:
3. Enhancement on SRS, targeting both FR1 and FR2:
4. Enhancement on CSI measurement and reporting:
– Investigate if the requirements on link recovery procedure are suitable for FR2 serving cells [RAN2, RAN4]
– Specify core requirements associated with the items specified by RAN1 [RAN4]
Qualcomm recently reported that Release 17 brings further enhancements to the foundational aspects of the 5G system, pushing the technology boundaries on many fronts, including capacity, coverage, latency, power, mobility, and more. The chip maker noted that further enhanced massive MIMO was one of the key areas of improvement. “Release 17 project focused on a few key areas of technology enhancements, including enhancements to multi-TRP (transmission and reception points) and multi-beam operations, as well as improvements in SRS (sounding reference signals) triggering/switching and CSI (channel state information) measurement/reporting,” Qualcomm said.
