Abstract
A number of requirements for 5G mobile communication are satisfied by adopting multi-user multiple input multiple output (MU-MIMO) systems. The inter user interference (IUI) which is an inevitable problem in MU-MIMO systems becomes controllable when the precoding scheme is used. The proposed scheme, which is one of the precoding schemes, is built on regularized block diagonalization (RBD) precoding and utilizes the partial nulling concept, which is to leave part of the IUI at the same time. Diversity gain is obtained by leaving IUI, which is made by choosing the row vectors of the channel matrix that are not nullified. Since the criterion for choosing the row vectors of the channel is the power of the channel, the number of selected row vectors of the channel for each device can be unfair. The proposed scheme achieves performance enhancement by obtaining diversity gain. Therefore, the bit error rate (BER) performance is better and the computational complexity is lower than RBD when the same data rate is achieved. When the number of reduced data streams is not enough for most devices to achieve diversity gain, the proposed scheme has better performance compared to generalized block diagonalization (GBD). The low complexity at the receiver is achieved compared to GBD by using the simple way to remove IUI.
Highlights
Multiple input multiple output (MIMO) systems are key components of future wireless communication in terms of high data rate over a limited frequency resource
Since the dimension of the channel matrix which is decomposed by using singular value decomposition (SVD) at the proposed scheme is decreased by excluding the row vectors, the proposed scheme has low complexity at the transmitter compared to regularized block diagonalization (RBD)
The Rayleigh fading channel which is frequently used in wireless communication system is used
Summary
Multiple input multiple output (MIMO) systems are key components of future wireless communication in terms of high data rate over a limited frequency resource. BD scheme has enhanced performance compared to the ZF precoding and devices that have more than one antenna need to remove IAI. Generalized BD (GBD) [22] is the scheme that utilizes the partial nulling concept to get the transmit diversity gain by using SVD of the channel for each device and decreasing the number of data streams. In this paper, proposed scheme that combines RBD precoding method with partial nulling concept achieves performance enhancement due to the transmit diversity gain compared to RBD. The proposed scheme has better performance compared to the GBD and MGBD when the number of reduced data streams is not enough for most devices to achieve diversity gain. The proposed scheme is highly efficient compared to conventional schemes in respect of performance and complexity
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