Method for improving signal to noise ratio in an uplink transmission

A method for improving signal to noise ratio in an uplink transmission, the method comprising:

• receiving signals from “X” users at a plurality of antennas present in a plurality of base stations;
• determining a plurality of combinations of “N” possible users to be selected among the “X” users, wherein each of the “N” users is associated with one base station, such that each of the “N” users transmit to all the base stations, each comprising at least “n” number of antennas, where n>=N, wherein each of the “N” users transmit on a same sub-carrier;
• computing signal to noise ratio for each of the users among the determined combinations of “N” possible users by using signals received by all the antennas of all the base stations;
• and
• selecting at least one combination among the plurality of combinations of “N” possible users, such that, a combined signal to noise ratio of the selected combination is maximum among all combinations.

A method for improving signal to noise ratio in an uplink transmission, the method comprising:

• receiving signals from “X” users, each of the “X” users comprising two antennas, at a plurality of antennas present in a plurality of base stations;
• determining a plurality of combinations of “N” possible users to be selected among the “X” users, wherein each of the “N” users is associated with one base station, such that each of the “N” users transmit to all the base stations, each comprising at least “n” number of antennas, where n>=N, wherein each of the “N” users transmit on a same sub-carrier;
• computing signal to noise ratio for each of the users among the determined combinations of “N” possible users;
• and
• selecting at least one combination among the plurality of combinations of “N” possible users, such that, a combined signal to noise ratio of the selected combination is maximum among all combinations.

A method for accommodating multiple users transmitting on a same sub-carrier to a base station comprising n antennas, the method comprising:

• enabling a first user to transmit two bits through two antennas of a user equipment of the first user;
• decomposing a (n×2) channel matrix of the first user using Singular Value Decomposition (SVD), into three matrices, wherein the matrices are a (n×n) unitary matrix which is denoted by “U”, a (n×2) partial diagonal matrix which is denoted by “S” and a precoder (2×2) unitary matrix which is denoted by “VH”;
• enabling other (n−2) users in the base station to transmit one data bit each through two antennas to the base station on same sub-carrier as the first user;
• computing effective channel matrix of the first user;
• computing effective channel vectors of the (n−2) users using “U”;
• computing transmit precoders of the (n−2) users using “U”;
• and
• computing signal to noise ratio and decoding the input bits of the users by applying Interference Rejection Combining (IRC) function using the signals received by the n antennas of the base station and effective channel vectors of the first user and the (n−2) users.

A method for accommodating multiple users transmitting on a same sub-carrier to a base station comprising n antennas, the method comprising:

• computing precoder determination algorithm (PDA) values corresponding to “X” users, wherein for each of the “X” users “n” such PDA values are computed, wherein the PDA values [V,Θ]=ψ[U, h, k] where “V” is a precoder matrix used for transmitting bits, “Θ” is a scalar value, “U” is a unitary matrix, “h” is a channel matrix of that user and “k” is a value from 1 to “n”, thereby resulting in X*n PDA values;
• identifying a maximum value of “Θ” for each value of “k”, thereby resulting in “n” maximum values of “Θ” from the X*n PDA values;
• and
• selecting the users to which the “n” maximum values of “Θ” correspond, to transmit to a base station through two antennas in a same sub-carrier, wherein each of the selected users is allowed to transmit “m” number of bits to the base station, where “m” is the number of maximum values of “Θ” out of “n” maximum values of “Θ”, corresponding to respective selected user.