4G Evolution and Multiplexing Techniques with Solution to Implementation Challenges

Interference Mitigation Schemes for the Uplink of Massive Mimo in 5g Heterogeneous Cellular Networks

“…for the case in which the CSI is not available at the received side, using (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), the MIMO channel capacity becomes…”

“…Since the real and imaginary rounding errors will be no more than 1 2 , then we have from (3-10) that Then, we check if the new vectorh 1 is shorter thanh , i.e., the condition in (3-6) is verified, if not so, swap them and repeat the procedure. The correlation between two vectors and the length of the vectors are checked in (3)(4)(5)(6)(7)(8)(9)(10)(11) and (3)(4)(5)(6), respectively. If both conditions are fulfilled, we have the lattice-reduced matrixH.…”

“…The common choice that achieves a good balance between speed and quality is δ = 3 4 . The conditions in (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) are known as the size reduction and the Lovász basis swapping condition, respectively. The CLLL reduction is summarized in Algorithm 1.…”

“…Swap (k − 1)-th and k-th columns inR and T; From (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) and (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) we can see that although not guaranteeing to reduce the orthogonal deficiency for every realization of H, the CLLL algorithm yields a new basisH whose orthogonal deficiency has an upper bound which is strictly less than one [54]. In previous works, the CLLL algorithm has shown an excellent trade-off between the orthogonal deficiency and the computational complexity.…”

“…To compute an estimateẑ 0 of z 0 , the receiver employs an LR-SIC detector, as described in , based on the permuted matrixH 0 =H e P 0 followed by the quantization procedure (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). The order of the elements of the estimated vector is rearranged to the original order, yielding the final estimate:…”