Wake-up radio using IEEE 802.11 frame length modulation for Radio-On-Demand wireless LAN

Abstract

In this paper, we introduce Radio-On-Demand (ROD) wireless LAN (WLAN) in which access points (APs) are put into a sleep mode during idle periods and woken up by stations (STAs) upon communications demands. The on-demand wake-up is realized by a wake-up receiver which is equipped with each AP and is used to detect a wake-up signal transmitted by STA. In this paper, in order to reduce the hardware installation cost at STA, we advocate to utilize wireless LAN frames transmitted by each STA as a wake-up signal to awake the target AP. The STA generates a wake-up signal by devising WLAN signal: each STA creates a series of WLAN frames with different length to which the information on wake-up ID is embedded. The wake-up receiver extracts the wake-up ID from the received frames with a simple detector which ensures its low-power operation. We evaluate false negative (STA fails to wake up the target AP) and false positive (AP falsely wakes up without an intended wake-up signal) probabilities of our proposed on-demand wake-up scheme with computer simulations. The numerical results show that the proposed scheme achieves the false negative probability of about 10 −2 when the detection error ratio of '1' is less than 10 −3 . We also show that the false positive probability can be largely reduced by employing long WLAN frames to generate each wake-up signal. These results confirm that the proposed wake-up scheme is a promising approach to reducing wasteful energy consumed by idle APs in WLAN.

Exploiting burst transmission and partial correlation for reliable wake-up signaling in Radio-On-Demand WLANs

“…At a certain sample period T s , the envelope of the consecutive WLAN frames, including inter-frame spaces, is sampled to a sequence of bits r = {r j } by a one-bit A/D converter. In previous works [14], frame lengths are detected by counting the number of continuous '1's in r, and demodulated to a wake-up ID according to Const1. Then, ID matching can be conducted via either state transition or correlation.…”

“…To better exploit the firmware of off-the-shelf WLAN devices, a wake-up ID is modulated onto lengths of consecutive WLAN frames in [13], [14]. In this way, even a legacy node, after merely a software update, can transmit wakeup IDs.…”

“…APs experiencing long idleness are turned off, and through the attached wake-up receiver, are activated again in an on-demand way, by nodes initiating new data flows. A wake-up ID is modulated onto lengths of WLAN frames in a similar way as [13], [14]. Our contribution is two-fold in improving system reliability: (i) We exploit burst transmission of WLAN frames for delivering a wakeup ID, preventing non-wake-up frames from breaking in.…”

Receiver design for realizing on-demand WiFi wake-up using WLAN signals

“…This enables 802.11 device to send specific identification (e.g., wake-up ID) to the other sleeping device which is equipped with a secondary 802.15.4 device. We have also proposed in [10] a mechanism for WiFi STA to send wake-up ID to a sleeping access point (AP) which is equipped with a secondary wake-up receiver. The proposed approach does not require each STA to install extra hardware to generate wake-up signals while many idle APs can be transited into sleep mode, which can reduce significant amount of wasteful energy consumed by widely-spread WiFi APs [11][12] [13].…”

Green wireless local area network received signal strength dimensionality reduction and indoor localization based on fingerprint algorithm

“…the ubiquitous location-based services, such as emergency alert, targeted advertisement, and indoor navigation [4][5][6][7] In the wake of developments in WLAN, APs are being deployed in high density for bandwidth redundancy instead of just providing basic and complete coverage. It is understandable that this design makes WLAN work more steadily when hundreds of users simultaneously run their delay-sensitive and bandwidth-intensive applications [8,9]. But the redundant APs really introduce opportunities as well as challenges to the WLAN indoor localization.…”