No abstract

In this paper, we present a punctured scheduling scheme for efficient transmission of low latency communication (LLC) traffic, multiplexed on a downlink shared channel with enhanced mobile broadband traffic (eMBB). Puncturing allows to schedule eMBB traffic on all shared channel resources, without prior reservation of transmission resources for sporadically arriving LLC traffic. When LLC traffic arrives, it is immediately scheduled with a short transmission by puncturing part of the ongoing eMBB transmissions. To have this working efficiently, we propose recovery mechanisms for punctured eMBB transmissions, and a service-specific scheduling policy and link adaptation. Among others, we find that it is advantageous to include an element of eMBB-awareness for the scheduling decisions of the LLC transmissions (i.e. those that puncture ongoing eMBB transmissions), to primarily puncture eMBB transmission(s) that are transmitted with low modulation and coding scheme index. System level simulations are presented to demonstrate the benefits of the proposed solution.

In this article, we present a holistic overview of the agile multiuser scheduling functionality in 5G. An E2E perspective is given, including the enhanced QoS architecture that comes with 5G, and the large number of scheduling related options from the new access stratum sub-layer, MAC, and PHY layer. A survey of the 5G design agreements from the recently concluded 5G Study in 3GPP is presented, and it is explained how to best utilize all these new degrees of freedom to arrive at an agile scheduling design that offers superior E2E performance for a variety of services with highly diverse QoS requirements. Enhancements to ensure efficient implementation of the 5G scheduler for different network architectures are outlined. Finally, state-of-the-art system level performance results are presented, showing the ability to efficiently multiplex services with highly diverse QoS requirements.

No abstract

In this paper we present our latest findings on dynamic user-centric scheduling for a flexible 5G radio design, capable of serving users with highly diverse QoS requirements. The benefits of being able to schedule users with different transmission time intervals (TTIs) are demonstrated, in combination with a usercentric multiplexing of control and data channels. The proposed solution overcomes some of the shortcomings of LTE-Advanced in terms of scheduling flexibility and performance. In general it is found that using short TTIs is advantageous at low to medium offered traffic loads for TCP download to faster overcome the slow start phase, while at higher offered traffic loads the best performance is achieved with longer TTIs. Using longer TTI sizes results in less control overhead (from scheduling grants), and therefore higher spectral efficiency. The presented analysis leads to the conclusion that a future 5G design shall include support for dynamic scheduling with different TTI sizes to achieve the best performance.

In this paper, we present an exhaustive system level analysis of using preemptive scheduling for latency critical traffic in coexistence with mobile broadband for the 3GPP 5G New Radio. Enhanced recovery and HARQ retransmission mechanisms exploiting base station a priori knowledge of punctured radio resources from using preemptive scheduling are proposed. It is demonstrated that a scheme with HARQ multi-bit feedback and selective retransmission of punctured resources is an attractive solution. Furthermore, the performance sensitivity from using either fully interleaved or frequency-first code block layouts is assessed. The impact on the mobile broadband performance is evaluated at TCP-level, studying both the penalty on throughput and smoothened TCP round trip time to assess how preemptive scheduling affects the end-to-end performance of other traffic.

Data duplication is studied as a fundamental enabler for ultra-reliable low-latency communication (URLLC) in fifth-generation cellular systems. It entails the simultaneous usage of multiple radio links delivering redundant data between a terminal and the network to boost the transmission reliability. However, the improved reliability comes at a cost of reduced spectral efficiency, since the transmission of multiple instances of the data message on different links occupies more radio resources as compared to sending only one instance using a single link. It is therefore crucial to improve the performance of data duplication schemes, with the aim of reducing the radio resource consumption without degrading the reliability gain provided by this transmission paradigm. In this paper, we propose several methods to increase the downlink URLLC capacity supported by data duplication in fifth-generation cellular networks based on the New Radio standard. A single-user analytical model is derived to evaluate a combination of the proposed enhancements. The most promising solution, namely selective data duplication upon failure which entails a massive reduction of the overall number of duplicate transmissions, is finally evaluated by means of extensive multiuser system-level simulation campaigns. The simulation results with background mobile broadband traffic show that, in the investigated scenario, the proposed solution with 4 Mbps offered URLLC traffic outperforms the baseline approach for data duplication with 1 Mbps offered URLLC traffic, thus increasing the amount of URLLC user equipments that can be effectively sustained by the network.

Open Loop Power Control is an important technique providing adaptation of user transmit power. There are multiple factors like cell size, interference conditions, etc. that determine the optimal settings of power control (PC) parameters. In this paper, the impact of open loop PC parameter settings on the performance of LTE uplink (UL) in a co-channel heterogeneous network (HetNet) scenario with macro-and pico presented. Further, we study the difference in optimal PC settings for various network deployment scenarios and cell range extension (CRE) offsets in order to determine sensitivity of parameter settings. It is found that optimal PC parameters for one case can serve as good parameters for other network configurations as well. The conclusions are supported by results of system-level simulations.