  Integer-forcing (IF) linear receiver has been recently introduced for
multiple-input multiple-output (MIMO) fading channels. The receiver has to
compute an integer linear combination of the symbols as a part of the decoding
process. In particular, the integer coefficients have to be chosen based on the
channel realizations, and the choice of such coefficients is known to determine
the receiver performance. The original known solution of finding these integers
was based on exhaustive search. A practical algorithm based on
Hermite-Korkine-Zolotareff (HKZ) and Minkowski lattice reduction algorithms was
also proposed recently. In this paper, we propose a low-complexity method based
on complex LLL algorithm to obtain the integer coefficients for the IF
receiver. For the 2 X 2 MIMO channel, we study the effectiveness of the
proposed method in terms of the ergodic rate. We also compare the bit error
rate (BER) of our approach with that of other linear receivers, and show that
the suggested algorithm outperforms the minimum mean square estimator (MMSE)
and zero-forcing (ZF) linear receivers, but trades-off error performance for
complexity in comparison with the IF receiver based on exhaustive search or on
HKZ and Minkowski lattice reduction algorithms.
