A study of capacity of 4-by-4 MIMO channel using leaky coaxial cables for linear-cells

Leaky coaxial (LCX) cable is widely used in wireless transmission communication systems as antenna for a long and narrow area called as linear-cell. We have proposed that one single LCX cable can be used as two antennas and the method to utilize one composite cable, which consists of a pair of LCXs with different radiation characteristics, to configure a multiple-input and multiple-output (MIMO) system. In this paper, we will study capacity of the proposed 4-by-4 LCX-MIMO system and compare its capacity with conventional MIMO system using omnidirectional antennas over 2.4GHz band. We also investigate the capacity difference if the spacing of two LCX cable is changed over 5GHz band. The results over 2.4GHz band show that the proposed system can reduce the space requirement for MIMO deployment for wireless application over linear-cell environments. The capacity results show that proposed LCX-MIMO channel has larger capacity than that of using monopole antennas at both sides. Over 5GHz band, the proposed LCX-MIMO channel using WF allocation scheme can have the capacity near to that of independent and identically distributed (i.i.d.) channel. It has good channel capacity even if the spacing between the pair of LCXs is as small as 2cm. On the other hand, the capacity can be largely improved using the simple EP allocation scheme if the system utilize LCX cables to configure MIMO systems for both 2.4GHz and 5GHz bands.