Robust train-to-wayside video communications in tunnels using H.264 error-resilient video encoding combined with multiple antenna systems Imade Fahd Eddine Fatani a , Yann Cocheril b,⇑ , Crépin Nsiala b , Baptiste Vrigneau c , Marion Berbineau b , François-Xavier Coudoux a a Univ Lille Nord de France-F-59000 Lille, IEMN, UMR 8520, Department OAE, UVHC, France b Univ Lille Nord de France-F-59000 Lille, IFSTTAR, LEOST, F-59650 Villeneuve d’Ascq, France c Univ of Poitiers, Bvd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex, France article info Article history: Received 8 February 2011 Received in revised form 29 May 2012 Accepted 1 June 2012 Keywords: H.264 Multiple Description Coding (MDC) Region Of Interest (ROI) MIMO systems Orthogonal Spatial Multiplexing (OSM) Ray tracing Tunnel propagation Railway systems abstract With the development of driverless metro systems, the demand for high data rate train-to- wayside wireless transmission is increasing drastically in order to satisfy operational needs such as maintenance, video surveillance of the inside of the trains and passenger informa- tion. Thus, the association of new transmission techniques such as new video coding tech- niques, multi antennas at transmission and reception sides and recent precoders provides technically and economically efficient solutions to improve existing systems. This paper presents and evaluates two novel strategies to enhance train-to-wayside wireless video transmissions in tunnels using realistic channel models obtained with ray tracing previ- ously experimentally validated. Multiple Description Coding (MDC) or Region Of Interest (ROI) coding, using the new Flexible Macroblock Ordering (FMO) technique, is combined with appropriate Multiple Input Multiple Output (MIMO) schemes, namely, spatial multi- plexing (SM), orthogonal spatial multiplexing (OSM) and precoded orthogonal spatial mul- tiplexing (P-OSM) depending if full channel state information at transmitter side (CSI-T) is available or not. For each strategy, both video encoding process and MIMO algorithm are combined in an efficient way to provide the best video quality at the receiver with no increase of the number of radio access points along the infrastructure. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction With the development of driverless systems for metro, the need for efficient train-to-wayside wireless communication systems is increasing. These systems are developed to satisfy operational needs, such as traffic management, maintenance, information and security of passengers and staff. Two main families of applications can be distinguished. First, the safety- oriented applications devoted to control and command of vehicles also called CBTC (Communication Based Train Control). Second, the non-safety applications such as information for passengers, maintenance, and video monitoring of the inside of vehicles, also called CCTV (Closed-Circuit TeleVision) which constitute the major topic of this research paper. Recently, CCTV solutions have been developed by the guided transport industry using WLAN (Wireless Local Area Net- work) IEEE 802.11a/b/g existing modems considered as COTS (Commercial Of The Shelf) between 2 and 6 GHz (Fitzmaurice, 2006). We can mention deployed systems such as the Urbalis system of ALSTOM (Lausanne, Singapour, Shanghai), and the Airlink system of SIEMENS (Budapest line M2, Barcelona line 9, New York line 1...). 0968-090X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.trc.2012.06.001 ⇑ Corresponding author. Tel.: +33 320438338. E-mail addresses: yann.cocheril@ifsttar.fr (Y. Cocheril), vrigneau@xlim.fr (B. Vrigneau), marion.berbineau@ifsttar.fr (M. Berbineau), francois-xavier. coudoux@univ-valenciennes.fr (F.-X. Coudoux). Transportation Research Part C 25 (2012) 168–180 Contents lists available at SciVerse ScienceDirect Transportation Research Part C journal homepage: www.elsevier.com/locate/trc