PLS header coding for efficient signaling of modulation and coding schemes for broadband satellite communications systems
An approach is provided for an improved coding approach for efficient header signaling in broadband communications networks, to provide support of expanded modulation and coding scheme sets that facilitate an expansion of the operational ranges of user terminals within such networks and finer granularity within such operational ranges. A mode indicator field of a frame header identifies a modulation/coding mode applied to a data payload of the data frame. The modulation/coding mode is one of either a first or second set of modulation/coding modes. The mode indicator field is encoded and modulated. When the modulation/coding mode is one of the first set, the modulation of the encoded mode indicator field is applied in a first mode, and when the modulation/coding mode is one of the second set, the modulation of the encoded mode indicator field is applied in a second mode.
1. A method comprising:
generating a mode indicator field for identifying a modulation and coding mode applied to a data payload of a data frame of a communications network, wherein the modulation and coding mode is one of either a first set of modulation and coding modes or a second set of modulation and coding modes;
encoding the mode indicator field; and
modulating the encoded mode indicator field, wherein: (1) when the modulation and coding mode is one of the first set of modulation and coding modes, the modulation of the encoded mode indicator field is applied in a first mode; and (2) when the modulation and coding mode is one of the second set of modulation and coding modes, the modulation of the encoded mode indicator field is applied in a second mode.
2. The method of claim 1 , wherein the first mode for the modulation of the encoded mode indicator field comprises modulation in a first phase, and the second mode for the modulation of the encoded mode indicator field comprises modulation in a second phase.
3. The method of claim 2 , wherein the first phase for the modulation of the encoded mode indicator field is out of phase by approximately 90 degrees with respect to the second phase for the modulation of the encoded mode indicator field.
4. The method of claim 1 , wherein:
the mode indicator field comprises a plurality of bits reflecting respective binary values, and each binary value is associated with a respective modulation and coding mode of the first set of modulation and coding modes and with a respective modulation and coding mode of the second set of modulation and coding modes; and
for a given mode indicator binary value, the modulation of the encoded mode indicator field distinguishes between the associated modulation and coding mode of the first set and the associated modulation and coding mode of the second set.
5. The method of claim 4 , wherein, for the given mode indicator value, the modulation of the encoded mode indicator field in the first mode signifies the associated modulation and coding mode of the first set of modulation and coding modes, and the modulation of the encoded mode indicator field in the second mode signifies the associated modulation and coding mode of the second set of modulation and coding modes.
6. The method of claim 5 , wherein the data frame comprises a physical layer (PL) data frame and the mode indicator field comprises a modcod field of a physical layer signaling (PLS) field of a header of the PL data frame, the modulation of the encoded mode indicator comprises a π/2 binary phase shift keying (BPSK) modulation, and the first mode for the modulation of the encoded mode indicator field comprises modulation in a first phase, and the second mode for the modulation of the encoded mode indicator field comprises modulation in a second phase, wherein the first phase is out of phase by approximately 90 degrees with respect to the second phase.
7. A method comprising:
receiving a signal stream transmitted over a communications channel, wherein the signal stream comprises one or more data frames, and each data frame comprises a frame header and a frame data payload;
detecting a start of frame (SOF) field within the signal stream;
locating a frame header of a one of the data frames based on the detected SOF field, and demodulating and decoding a frame signaling field of the frame header;
determining a mode of modulation applied to the frame signaling field, and determining a mode indicator field of the frame signaling field; and
determining a modulation and coding mode applied to the frame data payload based on both the determined mode of modulation applied to the frame signaling field and the determined mode indicator field.
8. The method of claim 7 , wherein the mode of modulation applied to the frame signaling field comprises one of a modulation in a first phase and a modulation in a second phase.
9. The method of claim 8 , wherein the first phase for the modulation of the frame signaling field is out of phase by approximately 90 degrees with respect to the second phase for the modulation of the frame signaling field.
10. The method of claim 7 , wherein:
the mode indicator field comprises a plurality of bits reflecting respective binary values, and each binary value is associated with a respective modulation and coding mode of a first set of modulation and coding modes and with a respective modulation and coding mode of a second set of modulation and coding modes; and
for a given mode indicator value, the mode of modulation applied to the frame signaling field distinguishes between the associated modulation and coding mode of the first set and the associated modulation and coding mode of the second set.
11. The method of claim 10 , wherein, for the given mode indicator value, a determination that the mode of modulation applied to the frame signaling field is of a first mode signifies the associated modulation and coding mode of the first set of modulation and coding modes, and a determination that the mode of modulation applied to the frame signaling field is of a second mode signifies the associated modulation and coding mode of the second set of modulation and coding modes.
12. The method of claim 11 , wherein the data frames comprise physical layer (PL) data frames and the mode indicator field comprises a modcod field of a physical layer signaling (PLS) field of the frame header, the modulation applied to the frame signaling field comprises a π/2 binary phase shift keying (BPSK) modulation, and the first mode for the modulation applied to the frame signaling field comprises modulation in a first phase, and the second mode for the modulation applied to the frame signaling field comprises modulation in a second phase, wherein the first phase is out of phase by approximately 90 degrees with respect to the second phase.
13. An apparatus, comprising:
at least one processor; and
at least one memory including computer program code for one or more programs,
the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:
generating a mode indicator field for identifying a modulation and coding mode applied to a data payload of a data frame of a communications network, wherein the modulation and coding mode is one of either a first set of modulation and coding modes or a second set of modulation and coding modes;
encoding the mode indicator field; and
modulating the encoded mode indicator field, wherein: (1) when the modulation and coding mode is one of the first set of modulation and coding modes, the modulation of the encoded mode indicator field is applied in a first mode; and (2) when the modulation and coding mode is one of the second set of modulation and coding modes, the modulation of the encoded mode indicator field is applied in a second mode.
14. The apparatus of claim 13 , wherein the first mode for the modulation of the encoded mode indicator field comprises modulation in a first phase, and the second mode for the modulation of the encoded mode indicator field comprises modulation in a second phase.
15. The apparatus of claim 14 , wherein the first phase for the modulation of the encoded mode indicator field is out of phase by approximately 90 degrees with respect to the second phase for the modulation of the encoded mode indicator field.
16. The apparatus of claim 13 , wherein:
the mode indicator field comprises a plurality of bits reflecting respective binary values, and each binary value is associated with a respective modulation and coding mode of the first set of modulation and coding modes and with a respective modulation and coding mode of the second set of modulation and coding modes; and
for a given mode indicator binary value, the modulation of the encoded mode indicator field distinguishes between the associated modulation and coding mode of the first set and the associated modulation and coding mode of the second set.
17. The apparatus of claim 16 , wherein, for the given mode indicator value, the modulation of the encoded mode indicator field in the first mode signifies the associated modulation and coding mode of the first set of modulation and coding modes, and the modulation of the encoded mode indicator field in the second mode signifies the associated modulation and coding mode of the second set of modulation and coding modes.
18. The apparatus of claim 17 , wherein the data frame comprises a physical layer (PL) data frame and the mode indicator field comprises a modcod field of a physical layer signaling (PLS) field of a header of the PL data frame, the modulation of the encoded mode indicator comprises a π/2 binary phase shift keying (BPSK) modulation, and the first mode for the modulation of the encoded mode indicator field comprises modulation in a first phase, and the second mode for the modulation of the encoded mode indicator field comprises modulation in a second phase, wherein the first phase is out of phase by approximately 90 degrees with respect to the second phase.
19. An apparatus, comprising:
at least one processor; and
at least one memory including computer program code for one or more programs,
the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:
receiving a signal stream transmitted over a communications channel, wherein the signal stream comprises one or more data frames, and each data frame comprises a frame header and a frame data payload;
detecting a start of frame (SOF) field within the signal stream;
locating a frame header of a one of the data frames based on the detected SOF field, and demodulating and decoding a frame signaling field of the frame header;
determining a mode of modulation applied to the frame signaling field, and determining a mode indicator field of the frame signaling field; and
determining a modulation and coding mode applied to the frame data payload based on both the determined mode of modulation applied to the frame signaling field and the determined mode indicator field.
20. The apparatus of claim 19 , wherein the mode of modulation applied to the frame signaling field comprises one of a modulation in a first phase and a modulation in a second phase.
21. The apparatus of claim 20 , wherein the first phase for the modulation of the frame signaling field is out of phase by approximately 90 degrees with respect to the second phase for the modulation of the frame signaling field.
22. The apparatus of claim 19 , wherein:
the mode indicator field comprises a plurality of bits reflecting respective binary values, and each binary value is associated with a respective modulation and coding mode of a first set of modulation and coding modes and with a respective modulation and coding mode of a second set of modulation and coding modes; and
for a given mode indicator value, the mode of modulation applied to the frame signaling field distinguishes between the associated modulation and coding mode of the first set and the associated modulation and coding mode of the second set.
23. The apparatus of claim 22 , wherein, for the given mode indicator value, a determination that the mode of modulation applied to the frame signaling field is of a first mode signifies the associated modulation and coding mode of the first set of modulation and coding modes, and a determination that the mode of modulation applied to the frame signaling field is of a second mode signifies the associated modulation and coding mode of the second set of modulation and coding modes.
24. The apparatus of claim 23 , wherein the data frames comprise physical layer (PL) data frames and the mode indicator field comprises a modcod field of a physical layer signaling (PLS) field of the frame header, the modulation applied to the frame signaling field comprises a π/2 binary phase shift keying (BPSK) modulation, and the first mode for the modulation applied to the frame signaling field comprises modulation in a first phase, and the second mode for the modulation applied to the frame signaling field comprises modulation in a second phase, wherein the first phase is out of phase by approximately 90 degrees with respect to the second phase.