Reseatch On Power Allocation Optimization Of Multibeam For High-throughput Satellite

The increasing demand for high data rate services over the integrated satellite-terrestrial network has pushed for the development of millimeter-wave(mmWave)band high throughput satellites(HTS)with multibeams.However,existing multibeam HTS is with predetermined beam connection.Considering the mmWave channel is much more sensitive to the weather conditions than the conventional S/C/X band channels,it is important to allocate the limited transmission power to the beams that connect to the ground station in good state.Moreover,due to the huge distance and long propagation delay in the integrated satellite-terrestrial networks,the multibeam HTS can only obtain delayed channel state information(CSI)from feedback.In paper,we model this problem as a partially observable markov decision process(POMDP),and propose a power allocation optimization over two identical Gilbert-Elliott beams HTS communication,which can partly mitigate the negative effects of adverse weather conditions.The key thresholds for selecting the optimal power allocation method in the multibeam HTS communications are derived.The effectiveness and potentialities of our proposed scheme is verified through simulation results.Considering the single-beam point-to-point typical transmission scenario of spatial information network,the second chapter combines the buffer overhead and establishes a single-beam point-to-point transmission strategy model through Lyapunov theory.The model is suitable for point-to-point transmission scenarios.Compared with the POMDP model,it has the advantages of reducing computational complexity,good portability,etc.The most important feature is to eliminate the "dimension" disaster generated by POMDP.Convert models from long-term returns to one-step,immediate returns.With the explosive growth of space communication services,high-throughput satellites will use the Ka-band and higher millimeter-wave bands to serve future space information networks through multi-beam downlink transmission.Since the millimeter wave band is greatly affected by rain attenuation,the downlink is a time-varying channel,which requires reasonable on-satellite power allocation and improves data throughput.However,multi-beam HTS is difficult to obtain accurate CSI of the Ka-band downlink channel in real time,so in chapter 3,an adaptive beam power allocation scheme is designed for data transmission of two beams and multiple beams.The adaptive power allocation dynamically allocates transmission power according to different channel states,allocates power to a channel with good state,and avoids waste of resources caused by allocation to a channel with bad state.Then it is extended to the adaptive data transmission strategy based on multi-beam confidence probability and the derivation of key thresholds.The simulation proves that the scheme can effectively improve the data transmission rate and spectrum utilization.Further,it is considered that the error correction code technique is adopted so that even when power is allocated to a beam with a poor CSI,a part of information can be successfully transmitted,which is called lossy transmission.In chapter 4,the two-beam high-throughput satellite power optimization strategy for lossy transmission is studied.Five power optimization schemes are designed based on the previous time slot delay feedback CSI and the perceived CSI of the current time slot.That include allocate all power to a single beam,the power is equally distributed to two beams,sensing one single-beam,sensing beam-by-beam strategy,and a conservative strategy.Compared with the Ka-band fixed parameter data transmission scheme,it is verified that the designed adaptive transmission strategy can effectively improve the spatial communication data transmission throughput.