Robust MMSE Transceiver Designs for Downlink MIMO Systems with Multicell Cooperation

Figure 4

Convergence of the DCOA: duality gap, four Lagrange multipliers, and four per-antenna transmission power, as functions of the number of iterations under the per-antenna power constraint with 10log₁₀𝑃=15dB. (Legend: the 4 different colors in the two middle subplots and two lower subplots correspond to the 4 transmit antennas.)

(a)

(b)

(c)

(d)

(e)

(f)