Method of assigning network addresses in an in-flight entertainment system

• US 7,921,192 B2
• Filed: 03/26/2008
• Issued: 04/05/2011
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Trinquecoste, Frederic, Durrey, Florent
• Primary Examiner(s): Jaroenchonwanit; Bunjob
• Application Number:
  US12/055,525
• Publication Number:
  US 20080244048A1
• Time in Patent Office: 1,105 Days
• Field of Search: None
• US Class Current: 709/222
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]

Abstract

In an in-flight entertainment system implementing a wireless link between a network server S and wireless processing units SDB_i,j which each serve the individual devices of a plurality of seats GS_i,j of one and the same row, an identification i of the column in which a wireless processing unit SDB_i,j is positioned is carried out by providing for a sequential powering-up (PW_i-on) of the columns, the powering-up of a column col_i triggering at this instant known to the server the boot process BP for the devices SDB_i,j of this column, enabling the column to be identified i by a local duration measurement b_i,j supplied by an internal clock DT_i,j of these devices previously initialized at a known instant of the boot process BP.

Claims

1. A method of assigning a network address to each wireless device of a network in an aircraft, said wireless devices being able to exchange messages with a network server via at least one access point, each wireless device being placed in a position of a seat in a column of seats and powered by a power supply column specific to the associated column, wherein said method comprises the steps of:

sequentially powering-up wireless devices, for each column of seats, with a time delay of known duration between the powering-up in one column and the powering-up in a next column;

each one of the wireless devices sending a corresponding message to a network server, the corresponding message having a time indication specific to the wireless device, the sending of the corresponding message triggered by the powering-up of the corresponding wireless device;

the network server receiving the corresponding messages from the wireless devices and time stamping each of the corresponding messages with a corresponding timestamp based on an instant at which each of the messages is received;

the network server identifying a column of seats of each of the wireless devices based on the time indication specific to the wireless device and the corresponding timestamp.

2. The method of assigning a network address to each of the wireless devices of a network in an aircraft, according to claim 1, in which said time delay is from ten seconds to a few tens of seconds.

3. The method of assigning a network address to each of the wireless devices of a network in an aircraft, according to claim 1, in which said sequential powering-up triggers in a wireless device:

a). a boot process comprising an initialization of an internal clock,

b). after said initialization, sending to the network server of at least one acknowledgement packet by said wireless device, said at least one acknowledgement packet comprising a current value of the internal clock of said wireless device at the moment of said sending the at least one acknowledgement packet and wherein the identification by the network server of the column of seats of the wireless device on reception of the at least one acknowledgement packet from the wireless device is performed on the basis of said current value contained in said at least one acknowledgement packet and the time of reception of said at least one acknowledgement packet supplied by the internal clock of the network server.

4. The method according to claim 3, in which each wireless device uses a packet sending mode of a type with packet receipt confirmation, and sends at determined intervals a new packet containing the corresponding current value of the internal clock, until a corresponding confirmation of receipt is received.

5. The method according to claim 3, in which the network server sends a column identification i to the wireless device sending the at least one acknowledgement packet in an acknowledgement of said at least one acknowledgement packet.

6. The method according to claim 3, such that, when an identification process is triggered, the network server executes the following steps:

a) activation of a loop for sequentially powering up wireless devices in columns of seats;

b) for i=0 up to n, n being an integer number corresponding to the number of columns;

i) i=i+1

ii) powering up of the column i;

iii) time delay, for a time delay duration then return to b)

c) for each received packet, storage of the current value transmitted in said received packet and of the local time of reception of the received packet by the network server;

d) for each pair (local reference value, local reception time), determination of an associated column number i.

7. The method according to claim 6, in which said column identification is given by the rank i of the column in the sequential powering-up loop and said column identification is performed by means of calculating the following equation:

i =(t_i,j−

t₁−

b_i,j−

s₀) / (Δ

+1), where s₀ is the average duration of a duration of the boot process of a wireless device between the instant at which the boot process is activated and the initialization of the internal clock of the wireless device, and t₁ is the instant when the first column is powered up by the sequential powering-up loop.

8. The method according to claim 7, in which the values s₀ and Δ

vary according to a system operating time.

9. In-flight entertainment system comprising a network server and wireless devices able to exchange messages with the network server via at least one access point, each wireless device being placed in the position of a seat in a column of seats and powered by a power supply column specific to the associated column, the network server supplies each wireless device with an identification of the column in which the wireless device is placed, by applying an address assignment process according to claim 1.