Contention-Based Nonorthogonal Massive Access with Massive MIMO

The sporadic communication character of massive machine-type communication systems provides natural advantages to utilize the principle of compressive sensing(CS).However,due to the high computational complexity of CS algorithms,CS-based contention-free access schemes have limited scalability and high computational complexity for massive access with user-specific pilots.To address these problems,in this paper,we propose a new contention-based scheme for CSbased massive access,which can support the sporadic access of massive devices(more than one million devices)with limited resources.Furthermore,an advanced receiver algorithm is designed to solve the optimal solutions for the proposed scheme,which utilizes various prior information to enhance the performance.In specific,the joint sparsity between the channel and data is used to improve the accuracy of pilot detection,and the information of modulation and cyclic redundancy check is exploited for channel correction to improve the performance of data recovery.The simulation results show that the proposed scheme can achieve improved active user detection performance and data recovery accuracy than existing methods.

WiGig and IEEE 802.11ad for Multi-Gigabyte-Per-Second WPAN and WLAN

The Wireless Gigabit Alliance （WiGig） and I EEE 802.11 ad are developing a multigigabit wireless personal and local area network （WPAN/ WLAN） specification in the 60 GHz millimeter wave band. Chipset manufacturers, original equipment manufacturers （OEMs）, and telecom companies are also assisting in this development. 60 GHz millimeter wave transmission will scale the speed of WLANs and WPANs to 6.75 Gbit/s over distances less than 10 meters. This technology is the first of its kind and will eliminate the need for cable around personal computers, docking stations, and other consumer electronic devices. High-definition multimedia interface （HDMI）, display port, USB 3.0, and peripheral component interconnect express （PCle） 3.0 cables will all be eliminated. Fast downloads and uploads, wireless sync, and multi-gigabit-per-second WLANs will be possible over shorter distances. 60 GHz millimeter wave supports fast session transfer （FST） protocol, which makes it backward compatible with 5 GHz or 2.4 GHz WLAN so that end users experience the same range as in today＇ s WLANs. IEEE 802.1 lad specifies the physical （PHY） sublayer and medium access control （MAC） sublayer of the protocol stack. The MAC protocol is based on time-division multiple access （TDMA）, and the PHY layer uses single carrier （SC） and orthogonal frequency division multiplexing （OFDM） to simultaneously enable low-power, high-performance applications.