A space-division time-division multiple access scheme for high throughput provisioning in WLANs

On the Design of MAC Protocols for Multi-Packet Communication in IEEE 802.11 Heterogeneous Networks Using Adaptive Antenna Arrays

“…In [18] the author observes that all the conditions required to exploit adaptive arrays in wireless networks can be completely satisfied only in a centralized MPT/MPR scenario. A MAC protocol for enabling MPR at 802.11 APs equipped with multi-beam antennas is proposed in [19] by adopting both space-division and time-division multiplexing. Experimental MPR testbeds are implemented in [20], where space-time multiplexing and conflict graphs are used to schedule the transmissions, in [21], where the access is managed by counting the active communications, and in [22], where the MAC protocol is designed accounting for the most suitable antenna configuration.…”

“…Accordingly, the task group n has developed the 802.11n amendment [7], which uses multi-antenna systems for increasing the data rate of the single link, but maintains the access limited to just one user at a time. To deal with this limitation, the benefits of advanced antenna systems for supporting multiple simultaneous communications have been explored by theoretical [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], and numerical/experimental studies [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35]. In this context the research efforts are currently focused on three main topics: the simultaneous transmission of different packets from a unique source to multiple destinations, known as multi-packet transmission (MPT), the simultaneous reception from multiple sources by a unique destination, known as multi-packet reception (MPR), and the concurrent communication between different node pairs, known as multi-packet communication (MPC).…”

“…MPT/MPR are widely considered suitable for centralized scenarios, where the synchronization is guaranteed by the AP [19], [20], [21], [22], [23], and [25], while, in distributed scenarios, the synchronization may be enabled by properly modifying the request-to-send/clear-to-send (RTS/CTS) handshake of the distributed coordination function (DCF) [24]. However, the results in [13] show that, for distributed scenarios, MPC is more suitable, since an asynchronous access can provide a higher throughput than a synchronous one.…”

Licence-exempt wireless communication systems

“…This is one area of ongoing research [12][13][14][15][16][17] into improving the performance of future wireless systems. And from a future perspective, one potential outcome of this research could be an automated co-operative control system that effectively removes the need for a frequency planning stage prior to deploying a wireless network.…”

An Uplink Medium Access Protocol with SDMA Support for Multiple-Antenna WLANs

“…The new IEEE 802.11n draft [3] takes Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) as the physical layer solution, which greatly increases the transmission rate by using spatial diversity or multiplexing. On the other hand, facilitating multiple transmissions or receptions in WLANs has been proposed recently [5] [6] [7] [8] [9], which is mostly realized by using Spatial Division Multiple Access (SDMA) with multiple antennas equipped on the access point (AP) and the user stations. Adopting SDMA in multiple-antenna WLANs is beneficial due to the following reasons.…”