A Two-Stage QoS Aware Scheduler for Wireless LANs Based on MIMO-OFDMA-SDMA Transmission

In this paper, a QoS-aware cross-layer scheduler for wireless LANs is introduced which can handle parallelised transmissions which are provided by OFDMA or SDMA. The scheduler includes two stages: in the hardware-independent stage, data flows are selected according to their QoS requirements such as throughput and delay. In the hardware-dependent stage, the channel resources are adaptively allocated to the flows according to the user priorities. All flows with a sufficiently high channel capacity are transmitted in parallel by assigning different OFDMA subcarriers or different spatial subchannels to the users. It is shown that the proposed QoS aware scheduler efficiently uses the channel resources in case of TDMA, OFDMA or SDMA and meets the quality-of-service requirements of time-critical flows under varying load and channel conditions.

[1]  Geoffrey Ye Li,et al.  Cross-layer optimization for OFDM wireless networks-part I: theoretical framework , 2005, IEEE Trans. Wirel. Commun..

[2]  Mats Bengtsson,et al.  Cross-layer scheduling for multi-user MIMO systems , 2006, IEEE Communications Magazine.

[3]  Cheng Wang,et al.  Optimal downlink multi-user MIMO cross-layer scheduling using HOL packet waiting time , 2006, IEEE Transactions on Wireless Communications.

[4]  Gerhard Wunder,et al.  Optimal and low complex suboptimal transmission schemes for MIMO-OFDM broadcast channels , 2005, IEEE International Conference on Communications, 2005. ICC 2005. 2005.

[5]  David Gesbert,et al.  Channel predictive proportional fair scheduling , 2008, IEEE Transactions on Wireless Communications.

[6]  Preben E. Mogensen,et al.  A stochastic MIMO radio channel model with experimental validation , 2002, IEEE J. Sel. Areas Commun..

[7]  Holger Boche,et al.  The interplay of link layer and physical layer under MIMO enhancement: benefits and challenges , 2006, IEEE Wireless Communications.

[8]  Petar Popovski,et al.  Proportional fairness in multi-carrier system: upper bound and approximation algorithms , 2006, IEEE Communications Letters.

[9]  Holger Boche,et al.  Stability-optimal transmission policy for the multiple antenna multiple access channel in the geometric view , 2006, Signal Processing.

[10]  Guocong Song,et al.  Utility-based resource allocation and scheduling in OFDM-based wireless broadband networks , 2005, IEEE Communications Magazine.

[11]  Harish Viswanathan,et al.  Downlink capacity evaluation of cellular networks with known-interference cancellation , 2003, IEEE J. Sel. Areas Commun..

[12]  Andreas Timm-Giel,et al.  An Enhanced Cross-Layer Two-Stage Scheduler for Wireless LANs , 2007, 2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications.

[13]  Geoffrey Ye Li,et al.  Cross-layer optimization for OFDM wireless networks-part II: algorithm development , 2005, IEEE Transactions on Wireless Communications.

[14]  A. Timm-Giel,et al.  A Cross-Layer Two-Stage Scheduler for Wireless LANs , 2007, 2007 16th IST Mobile and Wireless Communications Summit.