International Journal of Wireless Communications and Mobile Computing 2016; 4(5): 76-80 http://www.sciencepublishinggroup.com/j/wcmc doi: 10.11648/j.wcmc.20160405.12 ISSN: 2330-1007 (Print); ISSN: 2330-1015 (Online) Orthogonal Space Time Block Code for Four Time Slots for Uplink Transmission Hala M. Abd Elkader 1 , Gamal M. Abdel-Hamid 2 , Adly S. Tag El-Dien 1 , Asmaa A. Nassif 1, * 1 Electric Department, Banha University, Cairo, Egypt 2 Electric Department, Military Technical College, Cairo, Egypt Email address: gmabrouk@hotmail.com (G. M. Abdel-Hamid), adlymerg@yahoo.com (A. S. T. El-Dien), asmaa.nassef@feng.bu.edu.eg (A. A. Nassif) * Corresponding author To cite this article: Hala M. Abd Elkader, Gamal M. Abdel-Hamid, Adly S. Tag El-Dien, Asmaa A. Nassif. Orthogonal Space Time Block Code for Four Time Slots for Uplink Transmission. International Journal of Wireless Communications and Mobile Computing. Vol. 4, No. 5, 2016, pp. 76-80. doi: 10.11648/j.wcmc.20160405.12 Received: November 7, 2016; Accepted: November 26, 2016; Published: December 23, 2016 Abstract: In this paper, a new proposed space-time code for four-time slots and two transmitters for uplink transmission in a mobile system is presented. The mobile system needs three or four-time slots for data transmission. Also, this code is applied for multi-input multi-output (MIMO) fading channel. The proposed orthogonal space-time code achieves the properties of space-time code such as a full rate, full diversity, and non-vanishing minimum determinant value (MDV). The coding gain of this code is high because it achieves the trace or determinant criterion. Also, the proposed code needs a linear maximum likelihood (ML) decoding to decode four real symbols. Simulation results show that the performance of the proposed code is better than the performance of the previously presented schemes that are used in a mobile system for different modulation and diversity. Keywords: Orthogonal Space-Time Block Code, BER, Maximum Likelihood Decoding, MIMO System 1. Introduction Orthogonal space- time block code (OSTBC) and quasi- orthogonal (Q-OSTBC) are popular codes for uplink transmission (from the mobile system that has two antennas to the base station that has one or more antennas) in long term evolution-advanced (LTE-A) system. STBC is an open loop system. So, it needs channel state information at the receiver only. In LTE-A, There are three or four time slots for data transmission. Different STB codes are proposed for data transmission in this system. Orthogonal Alamouti space-time block code (STBC) is for two-time slots and two transmit antennas. So it can’t be used in the uplink transmission [1]. A hybrid scheme has three-time slots (two-time slots Alamouti code and one-time slot repetition transmission) but it doesn’t provide full diversity [2]. Quasi-orthogonal space-time block code that used three-time slots and two transmitters and achieved full rate and full diversity has been proposed in [3]. The maximum likelihood (ML) decoding of this code needs a joint detection of two complex symbols. In [4], a group decodable STBC with three-time slots and two transmit antennas which are suitable for the 3GPP LTE uplink frame structure was constructed. This code achieves full-rate, full diversity for all information symbols and ML detection complexity of order O (M), where M is the size of the symbol constellation. In [5], a novel STBC scheme for three-time slots and two transmit antennas was proposed. It achieves the properties of STBC such as full rate and full diversity, and non-vanishing minimum determinant value (MDV). Also, it has three real symbols decoding complexity. In [6], an efficient STBC that is used for the mobile system was proposed. Its ML decoding required a joint detection of three real symbols and its performance is better than [4, 5] at high signal to noise ratio. The proposed code in [7] is introduced for frame structure of LTE-A system with four-time slots and two antennas, this orthogonal STBC achieves full rate, full diversity, and MDV property of STBC. Its ML decoding needs a joint detection of four real symbols, this code shows that its BER performance is better than BER performance of double