Research And Design On Mapping Rule And Constellation For Spatial Modulation

Spatial modulation(SM)is a brand new modulation technique for multiple-input multiple-output(MIMO)systems.It achieves spatial multiplexing gain by exploiting a single radio frequency(RF)chain.By virtual of its low-complexity and high-energy-efficiency,it has attracted a lot of attentions.As a modulation technique,the most im-portant is to improve its design flexibility and transmission reliability.In the context,following works are done in this thesis.1.SM via 3-D mapping is proposed to break through the limit of conventional SM on the number of transmit antennas.The design flexibility of SM is greatly improved.To enhance the system reliability,the 3-D constellation design is investigated giv-en the employed signal modulation.A design method through separately optimiz-ing the sub-constellations of each activated antenna is proposed.The optimality of the proposed method is proved when M-PSK is employed as signal modulation.For the other cases,a low-complexity sub-optimal method is proposed and can be easily extended to generalized spatial modulation(GSM).2.Generalized 3-D constellation design for SM is further investigated based on the system model proposed in work 1.By selecting the data symbols from the com-plex field instead of a finite alphabet set,the 3-D design problem is formulated as a hybrid discrete and continuous optimization.To solve it,an exhaustive design method and a recursive design method are proposed resulting in better designs than those in literature.3.The adaptive bits-to-symbol mapper designs for SM are firstly investigated.Tak-ing the simplified SM-space shift keying(SSK)as object to study,an OBSA based mapper design and a low-complexity POBSA based on mapper design are proposed with channel state information at transmitter(CSIT).Considering lim-ited feedback,a RBSA based mapper design and a PRBSA based mapper design with low-complexity lightweight-feedback are proposed.The performance im-provement brought by the proposed adaptive mappers in reliability improvement and signal-to-noise(SNR)gain are analyzed and are validated by Monte Carlo simulations.The proposed designs are capable of offering considerable gain at no cost on additional hardware(e.g.,additional power amplifier,phase shifter,etc).Furthermore,the proposed designs and other link adaptive techniques can be used together to provide more gain.4.To address the problem that the mapper designs for SSK are not appropriate for S-M due to heavy feedback overhead and high computational complexity,a mapper design named brute forth mapper(BFM)is further proposed for SM,especially for SM employing large-cardinality signal modulation.Theoretical performance im-provement in reliability enhancement,that in SNR gain,the computational com-plexity and the amount of feedback information are all analyzed.Both analysis and simulation results show that the proposed BFM offers considerable gain with lightweight feedback overhead.In summary,this thesis proposes 3-D jointly mapped spatial modulation(JM-SM),in-vestigates the generalized 3-D constellation design and develops several link adaptive mappers to improve the transmission reliability of SM based on different feedback infor-mation.All these works offer SM more design flexibility,better performance and make SM more promising for future practical use.