QoS-equilibrium slot allocation for beam hopping in broadband satellite communication systems

Abstract

In broadband satellite communication systems, beam hopping (BH) is more and more welcome to compensate the low-power-efficiency wide beam and the lowspectrum-efficiency multiple spot beams simultaneously. As a flexible coverage method, BH demands efficient hopping strategy to reach the desired quality of service (QoS). In this paper, we consider the QoS equilibrium, in particular the delay fairness, among different cells illuminated by one hopping beam through designing the hopping strategy on the condition of capacity satisfaction. Due to the physical limitation that hopping speed is much slower than packet arrival speed, the ideal first-come-first-serve packet scheduling is not realizable, which compels us to pursuit the optimal slot scheduling instead. In this paper, we consider a long-term delay fairness problem by perperiod slot allocation for BH, using instantaneous and statistical information. To deal with the complex stochastic programming problem, we introduce the time-sharing principle to uncouple the variables and adopt stochastic gradient theory to deduce the suboptimal close-form solution. Our contributions are in three folds: firstly, it is the first time to consider the delay fairness not the traditional capacity fairness for BH; secondly, a general per-period decision scheme is proposed for the unique slot allocation in the perspective of queuing; thirdly, a suboptimal closeform solution for the per-period slot allocation is obtained, which could also cope with burst traffic cases. In simulation, we verify our method's advantage in terms of delay fairness comparing with the existing similar works.

Optimization Method of Dynamic Beam Position for LEO Beam-Hopping Satellite Communication Systems

“…In [20], a beam resource management algorithm that adjusts the beam size according to the traffic distribution was proposed, which can let more users access the satellite and make full use of beam bandwidth resources by covering more beam positions. In [21], Han et al focused on the delay fairness of each cell in the BH system, and a delay fairnessoriented BH algorithm was proposed. In [22]- [24], BH was combined with deep learning or deep reinforcement learning, which provides a novel optimization method to obtain the BH transmission scheme.…”

“…The literature review reveals that there is little research that focuses on the delay problem on BH satellite systems. The reference [21] pays attention to the delay fairness for BH satellite systems, but it didn't try to shorten the transmission delay. However, the transmission delay is a very important indicator for most users, which may determine whether users use the system or not.…”

“…It is noteworthy that the A c 1 , A c 2 , ..., A c Nc in (7) doesn't mean that when the ith cell's average packet arrival rate must be equal to Concerning the queueing delay, let Z (T ) denotes the summed packet number arriving into the satellite transponder during the period [0, T ], and N (t) denotes the packet number in time instant t in the satellite transponder. According to the queuing theory, the total queueing time overall the packets is the integral of the instantaneous packet number multiplied by time [21]. So the average queueing delay Q could be transformed into:…”

Deep reinforcement learning‐based beam Hopping algorithm in multibeam satellite systems

“…In this context, the BH technique emerged, where the multibeam satellite dynamically illuminates the cells with a small number of active beams. Many scholars have conducted the BH in satellite systems [12][13][14][15][16][17][18][19][20][21][22][23]. Angeletti et al [12] assessed the advantages in terms of system performance brought by the utilisation of BH technique and proposed GA based BH illumination plan (BHIP) optimisation.…”

“…Liu et al [17] studied a new method of rate control on the incoming traffic in the BH multibeam satellite systems. Different from works in [12][13][14][15][16][17] where the focus is on the capacity optimisation, Han et al [18] considered the delay fairness for the QoS equilibrium in BH satellites. To further improve the efficiency of on-board resource utilisation, joint BH and FRA [19], joint BH and precoding [20] schemes are proposed to improve the system performance.…”