In this letter, we propose a simple orthogonal
frequency-division multiplexing (OFDM) scheme for an asynchronous cooperative system, where OFDM is implemented at the source node, and time-reversion and complex conjugation are implemented at the relay nodes. The cyclic prefix (CP) at the source node is used for combating the timing errors the relay nodes.
In this scheme, the received signals at the destination node have the Alamouti code structure on each subcarrier, and thus, it has
the fast symbol-wise ML decoding. It should be emphasized that the relay nodes only need to implement the time-reversion, some sign changes plus to minus, and/or the complex conjugation to the received signals, and no IDFT or DFT operation is needed.It is shown that this simple scheme achieves second-order diversity
gain without the synchronization requirement at the relay nodes.
2022-09-23 22:00:59
105KB
企业仓库管理系统能够实现商品的入库、入库退货管理。实现商品的库存盘点管理。实现商品的库存调拨、出库管理。实现商品的库存上、下限管理。实现入库、入库退货、商品出库等查询管理。
2022-09-21 13:00:33
7.76MB