and the components can be a source of correlation with the 21cm signal. ]{} There are many works predicting the signal and the expected signal amplitude is less than $10^4 \rm \mu K^2$ depending on, for example, the duration and the timing of reionization [e.g. @2004PhRvD..70f3509C; @2006ApJ...647..840A; @2005MNRAS.360.1063S; @2008MNRAS.384..291A; @2010MNRAS.402.2279J; @2016ApJ...824..118A; @2017arXiv171205305M]. Simultaneously with the signal prediction, the less detectability has been shown [@Tashiro2008].

In this work, we calculate the 21cm-CMB cross power spectrum using MWA data and the CMB temperature map observed by the Planck experiment. [@Tashiro2008] have shown that a deep observation is required to detect the 21cm-CMB cross power spectrum using the MWA, as is such for the auto power spectrum. However, in order to reduce the noise effectively, systematic errors have to be less than the thermal noise. Then, to find unexpected systematics, an analysis using a common dataset is important before analyzing a large amount of data. Thus, the primary purposes of this work are to study the foreground and systematics contamination on the cross power spectrum analysis. Additionally, we attempt to remove the foregrounds from the MWA data to mitigate the systematic error.

The structure of this paper is as follows. The MWA data 