Patent ID: 8571121

Claim:
A method for Symbol Error Rate (SER) approximation of an SER-based transmission power allocation operation for an Orthogonal Space Time Block Code (OSTBC) in a Distributed Wireless Communication System (DWCS) equipped with multiple transmission Distributed Antennas (DA) geographically dispersed at random, the method for SER approximation comprising the steps of: setting a plurality of multiple combinable antenna subsets from dispersed multiple Das; selecting quasi-optimal antenna subsets, each quasi-optimal antenna subset A g (1≦g≦2 n −1) having a quasi-optimal power allocation weight w g based on a predetermined power allocation, for each one of the plurality of multiple combinable antenna subsets; calculating a plurality of SER approximation values of the selected quasi-optimal antenna subsets by applying a Probability Density Function (PDF) of a Signal-to-Noise Ratio (SNR) to a OSTBC SER having a symbol constellation of a predetermined modulation scheme; determining an optimal SER approximation value to be equal to a minimum of the plurality of SER approximation values; and outputting the optimal SER approximation value to an encoder for optimal power allocation based on the optimal SER approximation value; wherein the OSTBC SER includes at least one among an OSTBC SER having Multiple Quadrature Amplitude Modulation (MQAM) symbols, an OSTBC SER having M-ary Phase Shift Keying (MPSK) symbols, an OSTBC SER having Binary Phase Shift Keying (BPSK) symbols, and an OSTBC SER having Quadrature Phase Shift Keying (QPSK) symbols; and wherein the PDF of the SNR is defined by f η ⁡ ( x ) ≈ ∏ j = 1 g ⁢ ⁢ ( ∫ - ∞ + ∞ ⁢ ( 1 - si ⁢ ⁢ Ω j ⁢ w j ⁢ q j ⁢ ρ / m j ) - gm j ⁢ m ⁢ ⅇ - ⅈ ⁢ ⁢ sx ⁢ ⁢ ⅆ s ) 1 g = x m ⁢ ∑ j = 1 g ⁢ ⁢ m j - 1 ⁢ ∏ j = 1 g ⁢ ⁢ ( Γ ⁡ ( gm j ⁢ m ) ) - 1 g ⁢ ( Ω j ⁢ w j ⁢ q j ⁢ ρ m j ) - m j ⁢ m ⁢ ⅇ - m j ⁢ x Ω j ⁢ w j ⁢ q j ⁢ ρ ⁢ ⁢ g = x m ⁢ ∑ j = 1 g ⁢ ⁢ m j - 1 ⁢ ⅇ - ∑ j = 1 g ⁢ ⁢ m j ⁢ x Ω j ⁢ w j ⁢ q j ⁢ ρ ⁢ ⁢ g ⁢ ∏ j = 1 g ⁢ ⁢ ( Γ ⁡ ( gm j ⁢ m ) ) - 1 g ⁢ ( Ω j ⁢ w j ⁢ q j ⁢ ρ m j ) - m j ⁢ m = x D - 1 ⁢ ⅇ - x ⁢ ⁢ C 2 ⁢ C 1 , ⁢ wherein D = m ⁢ ∑ j = 1 g ⁢ ⁢ m j , ⁢ C 1 = ∏ j = 1 g ⁢ ⁢ ( Γ ⁡ ( gm j ⁢ m ) ) - 1 g ⁢ ( Ω j ⁢ w j ⁢ q j ⁢ ρ / m j ) - m j ⁢ m , ⁢ C 2 = ∑ j = 1 g ⁢ ⁢ m j / Ω j ⁢ w j ⁢ q j ⁢ ρ ⁢ ⁢ g , ⁢ η = SNR , ⁢ f η ⁡ ( x ) = PDF ⁢ ⁢ of ⁢ ⁢ η , w j =corresponding power allocation weight, ρ=Transmit Power to Receive Noise Ratio (TSNR), m j =corresponding Nakagami fading parameter, Ω j =the j th DA for large-scale fading, and g=combination of optimal DAs.