【NOMA】System-Level Performance of Downlink NOMA for Future LTE Enhancements(NOMA基础)

System-Level Performance of Downlink NOMA for Future LTE Enhancements

文章链接
目的：The goal is to clarify the performance gains of NOMA
we show that for both wideband and subband scheduling and both low and high mobility scenarios,NOMA can still provide a hefty portion of its expected gains even with error propagation
MA技术简介
Radio access technologies are typically characterized by multiple access schemes, e.g., frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and orthogonal frequency-division multiple access (OFDMA), which provide the means for multiple users to access and share the system resources simultaneously.
文章的贡献
The goal of this work is two-fold:

• The first is to clarify the gains of NOMA compared to OMA under more practical wide-area cellular system configurations with both wideband and subband frequency scheduling in both low mobility and high mobility environments;
• The second is to clarify the degree of impact of error propagation of SIC receiver, multi-user power allocation and user grouping on the performance of NOMA.
  这是一篇详细介绍NOMA技术原理的文章
  通信信道宽度: $BW$

划分子信道个数: $S$

无人机的传输能量限制: $P$

信道：SIMO信道，1-by-2 single input multiple output system

$N_{t}=1$, $N_{r}=2$ 一个发射天线，2个接收天线

子频带 $s$的用户集合 $\lbrace i_{s}(1),i_{s}(2),...,i_{s}(m_{s})\rbrace$总共有 $m_{s}$个用户

传输能量集合 $\lbrace P_{s}(1),P_{s}(2),...,P_{s}(m_{s})\rbrace$满足 $\sum_{i=1}^{m_{s}}P_{s}(i_{s}(i))=P$

传输信息率集合: $\lbrace d_{s}(i_{s}(1)),d_{s}(i_{s}(2)),...,d_{s}(i_{s}(m_{s})) \rbrace$

无人机发射出去的信号 $x_{s}=\sum_{l=1}^{m_{s}}\sqrt{P_{s}({i_{s}(l)})}d_{s}(i_{s}(l))$

由于用户采用了双天线，收到的信号强度为 $\bold {y_{s}}(i_s(l))=\bold {h_{s}}(w_s(i_{s}(l)))+\bold {w_{s}}(i_s(l))$

采取MRC接收机，用户接收到的符号为 $\check{y}(i_{s}(l))=\sqrt{G_{s}(i_{s}(l))}x_{s}+n_{s}(i_{s}(l))$

$\sqrt{G_{s}(i_{s}(l))}=\parallel\bold{h_{s}}(i_{s}^{2}(l))\parallel^{2}$
$n_s{i_s(l)}$是噪声，
$n_s(i_s(l))=\bold h_s^{H}(i_s(l))\bold w_s(i_s(l))/\parallel \bold h_s\parallel$

$SINR=\frac{G_{s}(i_{s}(l))P_{s}(i_s(l))}{\sum_{j \in U_s,\frac{G_s(i_s(l))}{N_s(i_s(l)}\lt\frac{G_s(i_s(j))}{N_s{(i_s(j))}}}G_s(i_s(j))P_s(j)+N_s(i_s(j))}$

时隙划分scheduler:

采用的是proportional fairness scheduler

$Q_s(U)=\sum_{k\in U}{\frac{R_s(k|U,t)}{L(k,t)}}$

$U_s=\max_{U}(Q_s|U)$

$\bold I^{*}=\arg\max_{\bold I}\prod_{\bold K\in \bold I}(1+\frac{R_{\bold K|\bold I}(t)}{(t_{c}-1)T_{\bold K}(t)})$

$R_{\bold K|\bold I}(t)$is the data rate of user $\bold K\in \bold I$,selecting $I$ as scheduling vector

power allocation 方案

分配给s波段的用户的能量 $P_{s}(k)=\frac{P}{\sum_{j\in U_{s}}{(G_s(j)/N_s(j))^{-\alpha_{FTPC}}}}(G_{s}(j)/N_s(j))^{-\alpha_{FTPC}}$

$\alpha_{FTPC}$是一个常数