Low-Complexity Scalable Iterative Algorithms for IEEE 802.11p Receivers

Abstract

In this paper, we investigate receivers for Vehicular to Vehicular (V2V) and Vehicular to Infrastructure (V2I) communications. Vehicular channels are characterized by multiple paths and time variations, which introduces challenges in the design of receivers. We propose an algorithm for IEEE 802.11p compliant receivers, based on Orthogonal Frequency Division Multiplexing (OFDM). We employ iterative structures in the receiver as a way to estimate the channel despite variations within a frame. The channel estimator is based on factor graphs, which allow the design of soft iterative receivers while keeping an acceptable computational complexity. Throughout this work, we focus on designing a receiver offering a good complexity performance trade-off. Moreover, we propose a scalable algorithm in order to be able to tune the trade-off depending on the channel conditions. Our algorithm allows reliable communications while offering a considerable decrease in computational complexity. In particular, numerical results show the trade-off between complexity and performance measured in computational time and BER as well as FER achieved by various interpolation lengths used by the estimator which both outperform by decades the standard least square solution. Furthermore our adaptive algorithm shows a considerable improvement in terms of computational time and complexity against state of the art and classical receptors whilst showing acceptable BER and FER performance.

Adaptive cooperative communications for enhancing QoS in vehicular networks

“…IEEE 802.11p is one of the commonly used standards for V2I and V2V to support communications in highly mobile, often densely populated, and frequently non-line-of-sight environments [7,8]. In addition, the IEEE 802.15.4 standard, comprising a simple physical (PHY) layer and energy efficient medium access control layer, is also designed to support both real-time and contention-based services and has been considered as a promising candidate for Internet of vehicles (IoV) and vehicular sensor networks [9].…”

Active jamming for multi-user information security improvement with the access statuses of users

“…The multiple served and idle users coexisting network is depicted in Figure . The depiction in Figure may be an abstraction from the vehicle‐to‐vehicle, vehicle‐to‐infrastructure, machine‐to‐machine, device‐to‐device, mobile social network, cloud radio access network, or homogeneous/heterogeneous network, and the node that provides services may represent a macro/micro base station, a relay, a terminal, or a centralized cloud service center . Moreover, each authorized user has two access statuses, that is, being served and idle, and each status may be switched into another one in each transmission time interval (TTI).…”

“…As we already know, with the ever‐increasing types of users and users' demands, diverse networks should appear in the next‐generation systems, such as LTE‐A and 5G . These networks may include the vehicle‐to‐vehicle network, vehicle‐to‐infrastructure network, machine‐to‐machine network, device‐to‐device network, mobile social network, self‐organization (e.g., ad hoc) network, sensor network, cloud radio access network, and macro/micro homogeneous or heterogeneous network . Further, there may be multiple users being served (through base station, relay, terminal, etc.)…”

An 802.11p Cross-Layered Pilot Scheme for Time- and Frequency-Varying Channels and Its Hardware Implementation

“…In [11], a receiver with iterative channel estimation making use of discrete prolate spheroidal sequences is proposed, and the receiver achieves FER performance close to the case with perfect CSI. A soft iterative receiver that uses factor graphs for performing joint channel estimation and detection is investigated in [12]. The receiver shows a significant FER performance improvement in comparison to the noniterative receivers.…”

“…The receiver shows a significant FER performance improvement in comparison to the noniterative receivers. It is also reported in both [11] and [12] that the insertion of a postamble enables reduction of the number of iterations required to attain a fixed performance. The iterative schemes discussed above suggest that it is possible to perform robust channel estimation using the existing pilot pattern at the cost of increased receiver complexity.…”