Patent ID: 7751468

Claim:
A method of estimating an SINR (signal to interference-plus-noise ratio) of an OFDM-CDMA transmission signal spread with spread codes, said transmission signal being transmitted between a transmission apparatus and a receiver apparatus, said method comprising: receiving the signal spread with spread codes at the receiver apparatus; and calculating, with a processor at the receiver apparatus, an estimate of the SINR ratio for the signal spread with the spread codes independently of a value of the spread codes according to a formula defined by: RSIB 0 ⁡ [ q ] = E ⁢  I 0  2 E ⁢  I 1  2 + E ⁢  I 2  2 + E ⁢  I 3  2 , wherein E ⁢  I 0  2 = P 0 ⁢  tr ⁡ ( G ⁡ ( q ) ⁢ A ⁡ ( q , q ) )  2 E ⁢  I 1  2 = P 0 ⁢ ∑ n = 0 n ≠ q D - 1 ⁢  tr ⁡ ( G ⁡ ( q ) ⁢ A ⁡ ( n , q ) )  2 E ⁢  I 2  2 = ⁢ α ⁢ ⁢ p _ ⁢ ∑ n = 0 D - 1 ⁢ ( tr ⁢ ( G ⁡ ( q ) ⁢ A ⁡ ( n , q ) ⁢ A ⁡ ( n , q ) H ⁢ G ⁡ ( q ) H ) - ⁢  tr ⁢ ( G ⁡ ( q ) ⁢ A ⁡ ( n , q ) )  2 ) E ⁢  I 3  2 = σ 2 ⁢ tr ⁡ ( G ⁡ ( q ) ⁢ G ⁡ ( q ) H ) I 0 represents an amplitude of the signal spread with spread codes for a user after equalization and correlation, I 1 represents interference generated by data of the user considered in other sub-bands, I 2 represents multiple access noise created by other spread codes, I 3 represents Gaussian noise filtered by an equalizer and sequence of the user considered, α is system load and p is average received power, P 0 is power of the signal spread with the spread codes for which the SINR is calculated, A and G are attenuation channel and equalization matrices, respectively, D is a number of data symbols per code on S T OFDM symbols, and q is a sub-band in which the SINR is calculated.