6,706 research outputs found
On the Performance of PDCCH in LTE and 5G New Radio
5G New Radio (NR) Release 15 has been specified in June 2018. It introduces
numerous changes and potential improvements for physical layer data
transmissions, although only point-to-point (PTP) communications are
considered. In order to use physical data channels such as the Physical
Downlink Shared Channel (PDSCH), it is essential to guarantee a successful
transmission of control information via the Physical Downlink Control Channel
(PDCCH). Taking into account these two aspects, in this paper, we first analyze
the PDCCH processing chain in NR PTP as well as in the state-of-the-art Long
Term Evolution (LTE) point-to-multipoint (PTM) solution, i.e., evolved
Multimedia Broadcast Multicast Service (eMBMS). Then, via link level
simulations, we compare the performance of the two technologies, observing the
Bit/Block Error Rate (BER/BLER) for various scenarios. The objective is to
identify the performance gap brought by physical layer changes in NR PDCCH as
well as provide insightful guidelines on the control channel configuration
towards NR PTM scenarios.Comment: Globecomm 2018 workshop, 6 pages, 7 fig
Configurable Distributed Physical Downlink Control Channel for 5G New Radio: ResourceBundling and Diversity Trade-off
New radio technologies for the fifth generation of wireless system have been
extensively studied globally. Specifically, air interface protocols for 5G
radio access network will be standardized in coming years by 3GPP. Due to its
crucial function in scheduled system, physical layer downlink control channel
(PDCCH) is a core element to enable all physical layer data transmissions.
Recently, configurable distributed PDCCH with the intention to cope with
different scenarios has been developed in 3GPP. To have comprehensive
understanding of respective technical advantages and potential scenario
dependent limitations, detailed performance analysis and evaluations of
configurable distributed PDCCH are thoroughly studied in this paper. In
particular, exponential effective SNR mapping (EESM) has been employed as the
performance metric of configurable distributed PDCCH in different scenarios. It
is demonstrated from EESM results that configurable distributed PDCCH offers
additional degree of freedom for the trade-off between achieved frequency
diversity and channel estimation gain by adjusting resource bundling level
according to the channel and interference scenario experienced by the control
channel transmission
Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites
Satellite Communication systems are a promising solution to extend and
complement terrestrial networks in unserved or under-served areas. This aspect
is reflected by recent commercial and standardisation endeavours. In
particular, 3GPP recently initiated a Study Item for New Radio-based, i.e., 5G,
Non-Terrestrial Networks aimed at deploying satellite systems either as a
stand-alone solution or as an integration to terrestrial networks in mobile
broadband and machine-type communication scenarios. However, typical satellite
channel impairments, as large path losses, delays, and Doppler shifts, pose
severe challenges to the realisation of a satellite-based NR network. In this
paper, based on the architecture options currently being discussed in the
standardisation fora, we discuss and assess the impact of the satellite channel
characteristics on the physical and Medium Access Control layers, both in terms
of transmitted waveforms and procedures for enhanced Mobile BroadBand (eMBB)
and NarrowBand-Internet of Things (NB-IoT) applications. The proposed analysis
shows that the main technical challenges are related to the PHY/MAC procedures,
in particular Random Access (RA), Timing Advance (TA), and Hybrid Automatic
Repeat reQuest (HARQ) and, depending on the considered service and
architecture, different solutions are proposed.Comment: Submitted to Transactions on Vehicular Technologies, April 201
5G new radio physical downlink control channel reliability enhancements for multiple transmission-reception-point communications
Non-coherent transmission from multiple transmission-reception-points (TRPs), i.e., base stations, or base station panels to a user equipment (UE) is exploited in 5G New Radio (NR) to improve downlink reliability and cell-edge throughput. Ultra reliable low-latency communications (URLLC) and enhanced Mobile BroadBand (eMBB) are prominent target use-cases for multi-TRP or multi-panel transmissions. In Third-Generation Partnership Project (3GPP) Release 17 specifications, multi-TRP-based transmissions were specified for the physical downlink control channel (PDCCH) specifically to enhance its reliability and robustness. In this work, a comprehensive account of various multi-TRP reliability enhancement schemes applicable for the 5G NR PDCCH, including the ones supported by the 3GPP Release 17 specifications, is provided. The impact of the specifications for each scheme, UE and network complexity and their utility in various use-cases is studied. Their error performances are evaluated via link-level simulations using the evaluation criteria agreed in the 3GPP proceedings. The 3GPP-supported multi-TRP PDCCH repetition schemes, and the additionally proposed PDCCH repetition and diversity schemes are shown to be effective in improving 5G NR PDCCH reliability and combating link blockage in mmWave scenarios. The link-level simulations also provide insights for the implementation of the decoding schemes for the PDCCH enhancements under different channel conditions. Analysis of the performance, complexity and implementation constraints of the proposed PDCCH transmission schemes indicate their suitability to UEs with reduced-capability or stricter memory constraints and flexible network scheduling
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