Technical Paper: This paper presents an assessment of the performance of the LTE-based 5G Terrestrial Broadcast system, popularly known as 5G Broadcast
Abstract
In this paper, we assess the performance of the LTE-based 5G Terrestrial Broadcast system, popularly known as 5G Broadcast, for two realistic Single Frequency Networks: the UK’s HPHT digital terrestrial TV (DTT) network and an example LPLT network with a 5 km inter-site distance (ISD) assembled from all the UK cellular networks appearing in Ofcom’s Sitefinder. Using the UK Prediction Model (UKPM), we first calculate the network coverage for fixed rooftop, indoor, portable and mobile reception environments. The coverage results are then combined with physical layer simulations to calculate the expected system throughputs.
We provide tables of capacity for a wide set of modulation and coding schemes (MCS) and channel models that will be useful to the industry to map specific coverage predictions to throughputs provided by the 5G Broadcast physical layer radio interface.
Finally, we evaluate the performance improvements, considering both physical layer performance and system capacity, that the implementation of Hybrid Automatic Repeat reQuest (HARQ) based time-interleaving may provide. Our results verify the significant system capacity improvements of time-interleaving in realistic mobile scenarios that motivate its potential standardisation into the next releases of the 3GPP technical specifications.
Introduction
The 3rd Generation Partnership Project (3GPP) Release-16 specifies enhancements to the Long Term Evolution (LTE) evolved Multimedia Broadcast Multicast Service (eMBMS), popularly known as 5G Broadcast (1), to address the 5G requirements for dedicated broadcast networks, previously identified in 3GPP TR 38.913 (2):
• A 100 µs Cyclic Prefix (CP) for high mobility (i.e. 250 km/h) support in Low Power Low Tower (LPLT) Single Frequency Networks (SFN) networks, with inter-site distances (ISD) up to around 15 km;
• A 300 µs CP for the support of conventional SFN i.e. broadcast networks with HighPower High-Tower (HPHT) sites with ISD of 60 - 80km or more, targeting fixed rooftop reception; and
• A more robust Cell Acquisition Subframe (CAS) for reliable signal acquisition and synchronisation.
5G Broadcast allows SFN transmissions with 100% of the resources allocated to broadcast capacity and supports receive-only mode (ROM) devices, i.e. without uplink capabilities1 (1).
In this paper, we focus on the performance of the Physical Multicast Channel (PMCH) for dedicated broadcast carriers for the numerologies shown in Table 1, where TCP is the duration of the CP (or guard interval), TU the active symbol period, and TEI the receiver’s channel equalisation interval (EI) (3). The performance of the CAS is not addressed in this paper.
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