Multi-amplitude Differential Space-time Block Coding Scheme for Square/Non-Square Code Matrix in MIMO Systems

Abstract

<p class="Abstract" style="margin: 0cm 0cm 0pt; layout-grid-mode: char;"><span style="font-size: x-small;"><span style="font-family: Times New Roman;"><span style="font-weight: normal;">Differential space-time coding (DSTC) technique has become a good choice when channel estimations are difficult to obtain in multiple antennas system. On the basis of analyzing the existing DSTC schemes, by introducing multi</span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">-</span><span style="font-weight: normal;">level quadrature amplitude modulation (MQAM) and matrix transform method, we develop a multi</span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">-</span><span style="font-weight: normal;">amplitude differential space-time block coding </span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">(STBC) </span><span style="font-weight: normal;">scheme for square</span><span style="font-weight: normal; mso-fareast-language: ZH-CN;"> or </span><span style="font-weight: normal;">non-square code matrix in </span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">MIMO systems</span><span style="font-weight: normal;">, and give the </span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">derivation of </span><span style="font-weight: normal;">calculation formula</span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">e</span><span style="font-weight: normal;"> of the coding advantage in detail. The developed scheme can effectively avoid the performance loss of conventional DSTC schemes based on PSK modulation (i.e. single amplitude DSTC) in high spectrum efficiency</span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">. It</span><span style="font-weight: normal;"> can be applied to non-square code matrix</span><span style="font-weight: normal; mso-fareast-language: ZH-CN;"> case</span><span style="font-weight: normal;">, </span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">and </span><span style="font-weight: normal;">thus overcomes the shortcoming that existing DSTC schemes </span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">are </span><span style="font-weight: normal;">only suit</span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">able for</span><span style="font-weight: normal;"> square code matrix. Compared with single amplitude DSTC schemes, our scheme has higher spectrum efficiency by carrying information not only on phases but also on amplitudes. Moreover, our scheme has linear decoding complexity, higher coding advantage, and higher code rate for more than two antennas. The simulations results show that the proposed scheme </span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">can provide</span><span style="font-weight: normal;"> lower BER </span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">than</span><span style="font-weight: normal;"> </span><span style="font-weight: normal; mso-fareast-language: ZH-CN;">the </span><span style...