This paper proposes a flexible pilot assignment method to jointly optimize the uplink and downlink data transmission in multi-cell Massive multiple input multiple output (MIMO) systems with correlated Rayleigh fading channels. By utilizing a closed-form expression of the ergodic spectral efficiency (SE) achieved with maximum ratio processing, we formulate an optimization problem for maximizing the minimum weighted sum of the uplink and downlink SEs subject to the transmit powers and pilot assignment sets. This combinatiorial optimization problem is solved by two sequential algorithms: a heuristic pilot assignment is first proposed to obtain a good pilot reuse set and the data power control is then implemented. Numerical results manifest that the proposed algorithm converges fast to a better minimum sum SE per user than the algorithms in previous works.

翻译：本文提出一个灵活的试点派任方法,以共同优化多细胞大规模多输入多重输出(MIMO)系统中的上链和下链数据传输。通过利用以最大比率处理实现的ERGodic光谱效率(SE)的封闭式表达方式,我们形成了一个优化问题,以最大限度地增加受传输权力和试点派任设置制约的SE上链和下链的最小加权总和。这种交错式优化问题通过两种顺序算法来解决:首先提出超常型试点派任,以获得良好的试点再利用数据集,然后实施数据功率控制。数字结果显示,拟议的算法快速将SE的每个用户的最小总和比以往工程的算法更接近。