| 摘要: | 毫米波（Millimeter wave，mmWave）是5G（5th generation wireless
systems，簡稱5G）無線通訊的重要技術，在高頻傳輸下，擁
有更高的資料傳輸速率（Data rate），同時有著更低的延遲，但是
在傳輸的過程中，卻有著相當大的損耗，以致於通訊品質大幅下
降。為了克服上述的影響，導入了波束成型（Beamforming）技術，
來為傳輸過程提供指向性，以降低損耗。在波束成型的架構中，
我們需要考量硬體成本、設計的複雜度還有可服務對象的數量，
綜合以上考量，我們選擇了混合波束成型（Hybrid Beamforming），
以取得在頻譜效率（spectral efficiency）以及成本上的平衡，混合波束成型中，每組射頻鏈（Radio Frequency chain，RF chain）透
過移相器（phase shifter）與每根天線連接，為了再更進一步的下
降成本，有人提出了子連結（sub-connected）架構，使得每組射
頻鏈只連結到對應的子陣列（sub array），來降低硬體成本及設
計複雜度，但因為射頻鏈沒有連結到每一根天線，導致頻譜效
率有所下降。在本文中，我們採用多路徑三維通道（multi-path
three-dimensional（3D）channel）為通道環境，並將擁有水平極化
（horizontal polarization）以及垂直極化（vertical polarization）的雙
極化天線（dual-polarized antenna）帶入通訊系統中，透過控制交
叉極化隔離（cross-polar discrimination，XPD），來增加訊號的集
中，以提升增益，並使用連續干擾消除（Successive Interference
Cancelation，SIC）算法，計算出預編碼器（precoder）和組合器
（combiner）的權重，以計算出其頻譜效率，最後再與全連結架構
（fully-connected）下的混合波束成型做比較。;Millimeter wave is an important technology for 5G (5th generation
wireless systems, 5G for short) wireless communication. Under highfrequency
transmission, it has a higher data transmission rate (Data rate)
and a lower delay. However, during the transmission process, However,
there is a considerable loss, so that the communication quality is greatly
reduced. In order to overcome the impact, we have introduced beamforming
technology to provide directivity for the transmission process to
reduce loss. In the beamforming architecture, we need to consider hardware
cost, design complexity, and the number of service objects. Basedon the above considerations, we chose hybrid beamforming to achieve
a balance between spectral efficiency and cost. In hybrid beamforming,
each radio frequency chain (RF chain) is connected to each antenna
through a phase shifter. In order to further reduce the cost, someone proposed
a sub-connected architecture, so that each radio frequency chain is
only connected to The corresponding sub-array is used to reduce hardware
cost and design complexity, but because the radio frequency chain
is not connected to each antenna, the spectral efficiency is reduced. In
this paper, we use a multi-path three-dimensional (3D) channel with the
dual-polarized antenna which had horizontal polarization and vertical polarization
into the communication system, by controlling the cross-polar
discrimination (XPD), the concentration of the signal is increased to increase
the gain, and the successive interference cancelation (SIC) algorithm
is used to calculate the weight of the precoder and combiner to
calculate its spectral efficiency, and finally compare it with the hybrid
beamforming under the fully-connected architecture. |
