In this paper,we propose a sub-6GHz channel assisted hybrid beamforming(HBF)for mmWave system under both line-of-sight(LOS)and non-line-of-sight(NLOS)scenarios without mmWave channel estimation.Meanwhile,we resort to ...In this paper,we propose a sub-6GHz channel assisted hybrid beamforming(HBF)for mmWave system under both line-of-sight(LOS)and non-line-of-sight(NLOS)scenarios without mmWave channel estimation.Meanwhile,we resort to the selfsupervised approach to eliminate the need for labels,thus avoiding the accompanied high cost of data collection and annotation.We first construct the dense connection network(DCnet)with three modules:the feature extraction module for extracting channel characteristic from a large amount of channel data,the feature fusion module for combining multidimensional features,and the prediction module for generating the HBF matrices.Next,we establish a lightweight network architecture,named as LDnet,to reduce the number of model parameters and computational complexity.The proposed sub-6GHz assisted approach eliminates mmWave pilot resources compared to the method using mmWave channel information directly.The simulation results indicate that the proposed DCnet and LDnet can achieve the spectral efficiency that is superior to the traditional orthogonal matching pursuit(OMP)algorithm by 13.66% and 10.44% under LOS scenarios and by 32.35% and 27.75% under NLOS scenarios,respectively.Moreover,the LDnet achieves 98.52% reduction in the number of model parameters and 22.93% reduction in computational complexity compared to DCnet.展开更多
The joint adoption of sub-6GHz and millimeter wave(mmWave)technology can prevent the blind spots of coverage,enabling comprehensive coverage while realizing high-speed communication rate.According to the sensitivity o...The joint adoption of sub-6GHz and millimeter wave(mmWave)technology can prevent the blind spots of coverage,enabling comprehensive coverage while realizing high-speed communication rate.According to the sensitivity of mmWave,base stations should be more densely deployed,which is not well described by existing Poisson hole process(PHP)and the Poisson point process(PPP)models.This paper establishes a sub-6GHz and mmWave hybrid heterogeneous cellular network based on the modified Poisson hole process(MPHP).In our proposed model,the sub-6GHz base stations follow the PPP,and the mmWave base stations(MBSs)follow MPHP distribution.The expressions of the coverage probability are derived by using the interference calculation method of integrating the nearest sector exclusion area.Our theoretical analysis has been verified through simulation results,suggesting that the increase in the cell radius decreases the coverage probability of signal-to-interference-plus-noise ratio(SINR),whereas the increase in the sector parameter has the opposite effect.The variation of sub-6GHz base stations(SBSs)density imposes more significant impact than the MBSs on the SINR coverage probability.In addition,the decrease in MBSs density will reduce the average bandwidth allocated to the user equipment(UE),thus reducing the rate coverage probability.展开更多
With the rapid development and commercialization of wireless communications,the execution of OTA testing requires a tremendous amount of test time.Therefore,test time reduction is of great significance.The objective o...With the rapid development and commercialization of wireless communications,the execution of OTA testing requires a tremendous amount of test time.Therefore,test time reduction is of great significance.The objective of this article is to determine optimal measurement grids for SISO OTA testing of 5G Sub-6 GHz user equipments(UEs)in anechoic chamber with satisfactory accuracy and efficiency.The effect of different grid configurations on OTA performance is analyzed quantitatively using reference radiation patterns at different bands.These patterns are utilized to mimic the worst-case radiation patterns of 5G Sub-6 GHz UEs.Subsequently,the associated measurement uncertainty(MU)terms are quantitatively analyzed and determined based on statistical analysis.According to the comparison of calculated MUs,reduction of grid points from currentlyrequired 62(30/30,Δθ/Δϕ)to 26(45/45)could achieve roughly 60%test time reduction for Sub-6 GHz,while still maintaining an uncertainty level of≤0.25 dB.These values can be further reduced to 14(60/60)with 80%reduction for Sub-3 GHz.More importantly,the recommended grid configurations in this research are applicable to both TIS and TRP testing.展开更多
基金supported in part by the National Natural Science Foundation of China under Grants 62325107,62341107,62261160650,and U23A20272in part by the Beijing Natural Science Foundation under Grant L222002.
文摘In this paper,we propose a sub-6GHz channel assisted hybrid beamforming(HBF)for mmWave system under both line-of-sight(LOS)and non-line-of-sight(NLOS)scenarios without mmWave channel estimation.Meanwhile,we resort to the selfsupervised approach to eliminate the need for labels,thus avoiding the accompanied high cost of data collection and annotation.We first construct the dense connection network(DCnet)with three modules:the feature extraction module for extracting channel characteristic from a large amount of channel data,the feature fusion module for combining multidimensional features,and the prediction module for generating the HBF matrices.Next,we establish a lightweight network architecture,named as LDnet,to reduce the number of model parameters and computational complexity.The proposed sub-6GHz assisted approach eliminates mmWave pilot resources compared to the method using mmWave channel information directly.The simulation results indicate that the proposed DCnet and LDnet can achieve the spectral efficiency that is superior to the traditional orthogonal matching pursuit(OMP)algorithm by 13.66% and 10.44% under LOS scenarios and by 32.35% and 27.75% under NLOS scenarios,respectively.Moreover,the LDnet achieves 98.52% reduction in the number of model parameters and 22.93% reduction in computational complexity compared to DCnet.
基金supported in part by the National Key R&D Program of China(2018YFE0100500)by the National Natural Science Foundation of China(61871387,61861041,and 62171354)by the Natural Science Basic Research Program of Shaanxi(2019JM-019).
文摘The joint adoption of sub-6GHz and millimeter wave(mmWave)technology can prevent the blind spots of coverage,enabling comprehensive coverage while realizing high-speed communication rate.According to the sensitivity of mmWave,base stations should be more densely deployed,which is not well described by existing Poisson hole process(PHP)and the Poisson point process(PPP)models.This paper establishes a sub-6GHz and mmWave hybrid heterogeneous cellular network based on the modified Poisson hole process(MPHP).In our proposed model,the sub-6GHz base stations follow the PPP,and the mmWave base stations(MBSs)follow MPHP distribution.The expressions of the coverage probability are derived by using the interference calculation method of integrating the nearest sector exclusion area.Our theoretical analysis has been verified through simulation results,suggesting that the increase in the cell radius decreases the coverage probability of signal-to-interference-plus-noise ratio(SINR),whereas the increase in the sector parameter has the opposite effect.The variation of sub-6GHz base stations(SBSs)density imposes more significant impact than the MBSs on the SINR coverage probability.In addition,the decrease in MBSs density will reduce the average bandwidth allocated to the user equipment(UE),thus reducing the rate coverage probability.
基金supported by the Beijing Natural Science Foundation under Grant L253002.
文摘With the rapid development and commercialization of wireless communications,the execution of OTA testing requires a tremendous amount of test time.Therefore,test time reduction is of great significance.The objective of this article is to determine optimal measurement grids for SISO OTA testing of 5G Sub-6 GHz user equipments(UEs)in anechoic chamber with satisfactory accuracy and efficiency.The effect of different grid configurations on OTA performance is analyzed quantitatively using reference radiation patterns at different bands.These patterns are utilized to mimic the worst-case radiation patterns of 5G Sub-6 GHz UEs.Subsequently,the associated measurement uncertainty(MU)terms are quantitatively analyzed and determined based on statistical analysis.According to the comparison of calculated MUs,reduction of grid points from currentlyrequired 62(30/30,Δθ/Δϕ)to 26(45/45)could achieve roughly 60%test time reduction for Sub-6 GHz,while still maintaining an uncertainty level of≤0.25 dB.These values can be further reduced to 14(60/60)with 80%reduction for Sub-3 GHz.More importantly,the recommended grid configurations in this research are applicable to both TIS and TRP testing.
