臺灣博碩士論文加值系統

空間多工為多輸入多輸出系統之一個主要的信號處理技術。空間多工技術能提供線性的容量增加而不需消耗額外的功率或頻寬。階層式時間-空間架構使用多天線陣列於傳送端與接收端，為空間多工之最顯著的利用。
於本論文中，我們討論用於階層式時間-空間（亦稱為垂直-階層式時間-空間）架構的偵測技術，對於單一及多使用者多輸入多輸出無線通訊系統。為了達到一個更好的折衷於運算複雜度與性能，我們提出一個簡易然而有效的分群偵測，其含有調適性群序式連續干擾消除法。新的方式由高到低，依功率強度來一群群連續地去除已偵測訊號。而值得注意的是，每群使用者的數目是調適地決定於後置訊號雜訊比的平均值，依此來得到較好的順序於信號處理。更明確而言，根據此取決於每階的門限，每一階段剩餘的信號被分成兩群：欲偵測群與剩餘群。在欲偵測群中為訊號雜訊比值的大於等於門限的使用者，在階層式時間空間信號處理之後，其將被去除。所有的過程將重複直到所有的使用者皆已被偵訊。新的方法能降低多重存取干擾於多使用者-多輸入多輸出系統，且調適性的消除多重位元流干擾於單使用著干擾於多使用者-多輸入多輸出系統與多使用者-多輸入多輸出系統。
從實驗結果顯示所提出的方法相較於以前的方法，在兩種方案下能達成接近，且有時甚至更好的位元錯誤率效能，但大量地減少複雜度與偵測延遲。

Spatial multiplexing (SM) is one of the major signaling techniques
in multiple-input multiple-output (MIMO) systems. The SM schemes
can provide a linear increase in the capacity without additional
power or bandwidth consumption. The layered space-time (LAST)
architectures use the multi-element antenna arrays (MEAs) at both
transmitter and receiver is the most notable exploitation of SM
schemes.

In this thesis, we discuss the detection techniques of the LAST
(also known as the vertical Bell Laboratories layered space-time
(V-BLAST) scheme) for both single user (SU) and multiuser (MU)
MIMO wireless communication systems. To strike a better tradeoff
between computational complexity and performance, a simple, yet
effective group detection with adaptive group order successive
interference cancellation (AGOSIC) is addressed. The new approach
sequentially peels off the detected signals group by group in a
descending order of power levels, and, most noticeable, the number
of users in each group are adaptively determined based on the
average of the post signal to noise ratio (SNR) to achieve a
better ordering of signals. More specifically, according to the
threshold, which is stage dependent, the remaining signals in each
stage are partitioned into two groups: the desired group and the
residual group. After conducting the layered space-time processing
scheme, the signals in the desired group, whose SNRs are all
greater than or equal to the threshold, are then removed. The
whole process is repeated until all users are detected. The new scheme can suppress the effect of multiple access
interference (MAI) in the MU-MIMO, and adaptively mitigate the
effect of multiple access interferences (MSI) in both SU-MIMO and
MU-MIMO.

Furnished simulations show that proposed scheme in both scenarios
can yield close and sometime even better than, bit error rate
(BER) performance as that of the previous works, but with
substantially reduced complexity and latency.

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