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Broadband low Earth orbit (LEO) satellite constellations are a reality. The integration of satellite and terrestrial systems for mobile communications is taking-off with the development of non-terrestrial networks (NTN) and the ongoing deployment of private constellations. Due to the highly mobile nature of LEO satellites, one of the critical research areas is the design of the mobility mechanisms to ensure robust service continuity for the end-user. Recent studies in the domain of Earth-moving cells have shown that measurement-based handover (HO) triggering events cannot guarantee a low number of radio link failures without an increase in signalling and measurement reporting. In this work, we present a new HO triggering event that exploits the predictable movement of LEO satellites and uses the distance between the user’s location and the centre of the moving cells on the ground. The performance of the proposed solution is evaluated with system-level simulations and compared against the measurement-based baseline HO and Rel-16 Conditional HO (CHO). It is found that the location-based HO triggering event completely eliminates the HO failures as well as unnecessary HOs and ping-pongs. As a result, the location-based HO triggering event extends the mean time-of-stay from values below 2 s to 4.8 s where the optimal mean time-of-stay is 4.9 s.

The development of non-terrestrial networks (NTN) aims to satisfy the requirements of ubiquitous and seamless coverage for fifth-generation (5G) services. Low Earth orbit (LEO) satellites introduce challenging mobility requirements to the 5G New Radio (NR) radio resource management procedures. Current research shows that the baseline 5G NR UE-assisted network-controlled handover (HO) procedure, meant for terrestrial scenarios, fails to ensure continuous and satisfactory service in LEO-based NTN. The conditional handover (CHO), specified by 3GPP in Rel-16, was designed for terrestrial networks to enhance mobility robustness by making HO decisions earlier. In this work, we conduct system-level simulations to evaluate the 5G NR mobility performance of the CHO in a LEO-based NTN with Earth-moving cells scenario. The simulation results show that the CHO procedure reduces the radio link failures and handover failures to 0 but increases the unnecessary HO rate by more than 60% in comparison with the baseline HO, which leads to an increase of the signalling and measurement reporting. Finally, future research directions are identified to address the increase of the signalling overhead by exploiting the predictability of the satellite’s movement.

Low-Earth orbit (LEO)-based satellite communication systems are envisioned to be a next-generation key asset for telecom industry due to their potential to deliver global and seamless mobile broadband services. The high-speed mobility relative to Earth, that characterizes LEO orbits, will pose time-varying propagation conditions impacting the system performance in terms of mobility, availability and user throughput. Therefore, in LEO satellite systems, it is fundamental to understand accurately the signal variations between mobile satellites and users on the ground. This paper presents a radio propagation model able to describe realistically the time variations of the LEO-to-Ground path loss, including the line-of-sight changes and the impact of the surrounding built-up structures. We propose a low-complexity geometrical approach based on intelligent ray-tracing that considers the general dependencies on the elevation angle. The resulting model has been validated for a suburban scenario, exhibiting an overall root mean square error of 1.1 dB. Furthermore, the time-correlated geometry-based model is suitable for system-level radio mobility simulations with LEO-to-Ground satellite systems.

A first network node (eNB) is configured to receive (404), from a second network node (UE), channel performance indicator values regarding a serving cell, and estimate (404) a number of network-coded packets based on the received channel performance indicator values, such that the estimated number of network-coded packets defines a number of network-coded packets required by the second network node for successful detection of payload data. The second network node is configured to generate (402) the value of a channel performance indicator regarding the serving cell, and cause (403) transmission of the generated value of the channel performance indicator to the first network node, wherein the generated value of the channel performance indicator directly or indirectly indicates the number of network-coded packets required by the second network node for successful reception of payload data that is an input to network coding.

If you are designing smartphone chipsets or operating a mobile network, you need to determine how certain parameters affect a speciic smartphone’s power consumption and igure out how to adjust the parameters to improve battery life. In this application note we show how to use the Agilent E6621A PXT wireless communications test set and the Agilent N6705B DC power analyzer to establish a power consumption model for LTE user equipment (UE). The model is useful when you need to examine the UE battery life in system-level simulations. We will explain how the Agilent equipment can be used in manual tests, but we do not discuss how to make automated tests (for example, using VEE software). In this application note, we analyze smartphones adhering to the 3GPP LTE standard [1].