arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1201.6282cs.NI
收藏

SDMA-OFDMA系统中的频率选择性调度增益

On the Frequency-Selective Scheduling Gain in SDMA-OFDMA Systems

Anatolij Zubow, Johannes Marotzke

摘要:

正交频分多址(OFDMA)是正交频分复用(OFDM)传输技术的多用户版本,其将宽带信道划分为多个正交窄带子信道,称为子载波。OFDMA系统利用频率分集(FD)增益和频率选择性调度(FSS)增益两者。FD增益通过将分布在整个频带上的子载波分配给用户来实现,而FSS增益通过将位于整个频带中的其它子带之中具有最有利的信道条件的小带宽的子带内的用户相邻子载波分配给用户来实现。多用户多输入多输出(MU-MIMO)是一种很有前途的技术,以提高频谱效率。公知的MU-MIMO模式是空分多址(SDMA),其可以在下行链路方向上使用以允许一组空间上可分离的用户共享相同的时间/频率资源。本文以WiMAX为例,研究了在SDMA-OFDMA系统中FSS的增益。因此,一个完整的SDMA-OFDMA MAC调度解决方案,同时支持FD和FSS的建议。在一个典型的城市宏小区的情况下,所提出的解决方案进行了分析,通过系统级的基于分组的模拟,详细的MAC和物理层的抽象。通过显式地模拟MAC层开销(MAP),其需要在OFDMA帧中用信号通知每个打包数据突发,我们可以呈现在MAC层处预期的整体性能。我们的研究结果表明,在一般情况下,从FSS的增益时,应用SDMA是低的。然而,在特定条件下,小数目的BS天线或大的信道带宽,可以从FSS获得显著的增益。

英文摘要:

Orthogonal Frequency Division Multiple Access (OFDMA) is a multi-user version of the Orthogonal Frequency Division Multiplexing (OFDM) transmission technique, which divides a wideband channel into a number of orthogonal narrowband subchannels, called subcarriers. An OFDMA system takes advantage of both frequency diversity (FD) gain and frequency-selective scheduling (FSS) gain. A FD gain is achieved by allocating a user the subcarriers distributed over the entire frequency band whereas a FSS gain is achieved by allocating a user adjacent subcarriers located within a subband of a small bandwidth having the most favorable channel conditions among other subbands in the entire frequency band. Multi-User Multiple Input Multiple Output (MU-MIMO) is a promising technology to increase spectral efficiency. A well-known MU-MIMO mode is Space-Division Multiple Access (SDMA) which can be used in the downlink direction to allow a group of spatially separable users to share the same time/frequency resources. In this paper, we study the gain from FSS in SDMA-OFDMA systems using the example of WiMAX. Therefore, a complete SDMA-OFDMA MAC scheduling solution supporting both FD and FSS is proposed. The proposed solution is analyzed in a typical urban macro-cell scenario by means of system-level packet-based simulations, with detailed MAC and physical layer abstractions. By explicitly simulating the MAC layer overhead (MAP) which is required to signal every packed data burst in the OFDMA frame we can present the overall performance to be expected at the MAC layer. Our results show that in general the gain from FSS when applying SDMA is low. However, under specific conditions, small number of BS antennas or large channel bandwidth, a significant gain can be achieved from FSS.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑