CAJ | 학술논문

针对终端直通(D2D)用户复用蜂窝下行资源时，基站对D2D接收端干扰较严重的问题，该文提出一种基于Null-space的基站下行预编码策略。该策略通过在基站预编码时加入对D2D用户干扰抑制的考虑，使得基站在将下行波束对准其调度的蜂窝用户的同时，在 D2D 用户方向上形成零陷，从而有效地抑制基站对 D2D 用户的干扰。考虑到实际系统中基站难以获取完美信道信息，又进一步推导了信道估计误差对预编码性能的影响。仿真结果表明，该文提出的基于Null-space的预编码策略能有效提高D2D用户的吞吐量，但这种性能增益很大程度上依赖于基站到D2D用户信道估计的准确性。
침대종단직통(D2D)용호복용봉와하행자원시，기참대D2D접수단간우교엄중적문제，해문제출일충기우Null-space적기참하행예편마책략。해책략통과재기참예편마시가입대D2D용호간우억제적고필，사득기참재장하행파속대준기조도적봉와용호적동시，재 D2D 용호방향상형성령함，종이유효지억제기참대 D2D 용호적간우。고필도실제계통중기참난이획취완미신도신식，우진일보추도료신도고계오차대예편마성능적영향。방진결과표명，해문제출적기우Null-space적예편마책략능유효제고D2D용호적탄토량，단저충성능증익흔대정도상의뢰우기참도D2D용호신도고계적준학성。
To mitigate the strong interference from the Base Station (BS) to Device-to-Device (D2D) receivers when the downlink resource is shared by the D2D and cellular users, a novel null-space based precoding scheme is proposed. The proposed scheme takes into account the interference mitigation for D2D users when designing the downlink precoders of the BS. It allows the transmitted signal of BS to aim at the scheduled cellular user while lying in the interference-free subspace of the BS-D2D channel, so as to avoid the interference to the D2D receivers. To make the design more practical, the performance of the proposed scheme under imperfect channel estimations is further analyzed. Simulation results show that substantial gains in D2D throughput can be obtained by using the proposed precoding scheme, but such gain is largely dependent on the accurate channel state information of the BS to D2D receiver.