Frame structure for adaptive data communications over a plastic optical fibre
The present invention relates to transmission and reception of data over a plastic optical fiber. In particular, the present invention provides for transmission and reception over the plastic optical fiber a particularly suitable frame structure. The frame structure includes a synchronization sequence and portions of user data alternating with alternating reference signal portions and control data portions. The length of the user data portions may be equal, the length of the synchronization sequence and the control data and reference signal portions may also be equal. The distances between the synchronization sequence and the reference signal portions and the control data portions are advantageously equal. The alternating of data and additional information avoids data decoding latency while maintaining the rate necessary for the additional information.
1. A method for transmitting user data over a plastic optical fibre including the steps of:
generating a synchronization sequence, a reference signal and a control signal;
forming a frame starting with the generated synchronization sequence and including a first plurality of portions for transmitting the user data, a second plurality of portions of the reference signal, and a third plurality of portions of the control data, wherein a portion of the first plurality of portions for transmitting the user data is located between any two of the generated synchronization sequence, a portion of the reference signal and a portion of the control data, and
transmitting the frame over a plastic optical fibre.
2. The method according to claim 1 , wherein
a distance in terms of frame timing between any two of the synchronization sequence, a portion of the reference signal and a portion of the control data is equal, and/or
a length in terms of frame timing of the synchronization sequence, a portion of the reference signal and a portion of the control data is equal, and/or
between any two portions of the reference signal there is a portion of the control data.
3. The method according to claim 1 , further comprising:
a step of low-power transmission or reception including respective transmitting or receiving substantially no power within the user data portions of the frame, and transmitting or receiving the synchronization sequence, the reference signal and the control information with a predetermined non-zero power.
4. The method according to claim 1 , wherein
the synchronization sequence is a predefined sequence of symbols modulated by a 2-level pulse-amplitude modulation,
the synchronization sequence, each reference signal portion, and each control data portion starts and ends with a zero-signal of a predefined length, and
wherein Tomlinson-Harashima precoding is applied to the user data.
5. The method according to claim 1 , wherein
the reference signal is a sequence of predetermined symbols modulated by an M-level pulse-amplitude modulation with M being an integer larger than 2.
6. The method according to claim 1 , wherein
the control data is modulated by a 2-dimensional binary phase shift keying 2-level pulse-amplitude modulation, 2D BPSK 2-PAM, coded with a forward error correction coding and included a cyclic redundancy check, and
the signal carrying the user data, and/or control data and/or reference signal and/or synchronization signal are scaled so as to guarantee substantially equal peak-to-peak optical power in transmission.
7. A method for receiving user data over a plastic optical fibre including the steps of:
receiving a signal over a plastic optical fibre,
detecting in the received signal a synchronization sequence indicating a start of a frame;
extracting from the frame a plurality of portions of a reference signal and control data, wherein a portion for transmitting the user data is located between any two of the synchronization sequence, a portion of the reference signal and a portion of the control data.
8. An apparatus for transmitting user data over a plastic optical fibre including:
a generator for generating a synchronization sequence, a reference signal and a control signal;
a frame assembler for forming a frame, the frame starting with the generated synchronization sequence and including a first plurality of portions for transmitting the user data, a second plurality of portions of the reference signal, and a third plurality of portions of the control data, wherein a portion for transmitting the user data is located between any two of the synchronization sequence, a portion of the reference signal and a portion of the control data, and
a transmitter for transmitting the frame over a plastic optical fibre.
9. The apparatus according to claim 8 , wherein
the distance in terms of frame timing between any two of the synchronization sequence, a portion of the reference signal and a portion of the control data is equal, and/or
the length in terms of frame timing of the synchronization sequence, a portion of the reference signal and a portion of the control data is equal, and/or
between any two portions of the reference signal there is a portion of the control data.
10. The apparatus according to claim 8 , further comprising:
a low-power transmission/reception unit for low-power transmission or reception including respective transmitting or receiving substantially no power within the user data portions of the frame, and transmitting or receiving the synchronization sequence, the reference signal and the control information with a predetermined non-zero power.
11. The apparatus according to claim 8 , wherein
the synchronization sequence is a predefined sequence of symbols modulated by a 2-level pulse-amplitude modulation, and
the synchronization sequence, each reference signal portion, and each control data portion starts and ends with a zero-signal of a predefined length, and
wherein Tomlinson-Harashima precoding is applied to the user data.
12. The apparatus according to claim 8 , wherein
the reference signal is a sequence of predetermined symbols modulated by an M-level pulse-amplitude modulation with M being an integer larger than 2.
13. The apparatus according to claim 8 , wherein
the control data is modulated by a 2-dimensional binary phase shift keying 2-level pulse-amplitude modulation, 2D BPSK 2-PAM, coded with a forward error correction coding and included a cyclic redundancy check, and
the signal carrying the user data, and/or control data and/or reference signal and/or synchronization signal are scaled so as to ensure substantially equal peak-to-peak optical power in transmission.
14. An apparatus for receiving user data over a plastic optical fibre, the apparatus including:
a receiver for receiving a signal over a plastic optical fibre,
a synchronizer for detecting in the received signal a synchronization sequence indicating a start of a frame;
a signal detector for extracting from the frame a plurality of portions of a reference signal, wherein a portion for receiving the user data is located between any two of the synchronization sequence, a portion of the reference signal and a portion of the control data.
15. The apparatus according to claim 14 , wherein
the distance in terms of frame timing between each two of the synchronization sequence, a portion of the reference signal and a portion of the control data is equal, and/or
the length in terms of frame timing of the of the synchronization sequence, a portion of the reference signal and a portion of the control data is equal, and/or
between each two portions of the reference signal there is a portion of the control data.
16. The apparatus according to claim 14 , further comprising:
a low-power transmission/reception unit for low-power transmission or reception including respective transmitting or receiving substantially no power within the user data portions of the frame, and transmitting or receiving the synchronization sequence, the reference signal and the control information with a predetermined non-zero power.
17. The apparatus according to claim 14 , wherein
the synchronization sequence is a predefined sequence of symbols modulated by a 2-level pulse-amplitude modulation, and
the synchronization sequence, each reference signal portion, and each control data portion starts and ends with a zero-signal of a predefined length, and
wherein Tomlinson-Harashima precoding is applied to the user data.
18. The apparatus according to claim 14 , wherein
the reference signal is a sequence of predetermined symbols modulated by an M-level pulse-amplitude modulation with M being an integer larger than 2.
19. The apparatus according to claim 14 , wherein
the control data is modulated by a 2-dimensional binary phase shift keying 2-level pulse-amplitude modulation, 2D BPSK 2-PAM, coded with a forward error correction coding and included a cyclic redundancy check, and
the signal carrying the user data, and/or control data and/or reference signal and/or synchronization signal are scaled so as to ensure substantially equal peak-to-peak optical power in transmission.
20. An integrated circuit embodying the apparatus according to claim 8 .