Method and system of providing efficient packetized voice communcations and data bearers in mobile satellite systems
A broadband satellite communications system comprises forward error correction (FEC) encoder/decoder, interleaver/deinterleaver, puncturing/de-puncturing, scrambler/descrambler, bit to symbol mapping/de-mapping devices, modulator/demodulator, transmit and receive filter; operating in a time-division multiple access (TDMA) system where information is sent in a burst-by-burst fashion during the assigned time slot; supporting diverse traffic types such as voice over internet protocol (VOIP), control messages (DACCH) and keep alive burst (KAB) during silence period and multiple data rates.
1. A method comprising:
generating, by a physical layer component of a communications device, a data transmission sequence comprising a plurality of data bursts of at least a first burst type, the first burst type being configured to carry a plurality of different data transmission types; and
transmitting, by the communications device, the data transmission sequence over a dedicated channel of a communications network;
wherein,
the plurality of data bursts includes two or more data bursts of the first burst type respectively carrying at least two different ones of the data transmission types,
each data burst of the first burst type consists of a uniform format irrespective of the data transmission type carried by the data burst,
each data burst of the first burst type comprises a unique word signature sequence that is unique to the data transmission type carried by the data burst providing for physical layer burst classification, and
in a case where a one of the data bursts of the first burst type carries VOIP data, the uniform format of the first burst type comprises an arrangement of the VOIP data in a manner whereby perceptually important bits and perceptually unimportant bits of the VOIP data are arranged relative to each other to maximize interleaving and coding gains in fading channels.
2. The method of claim 1 , wherein the plurality of different data transmission types comprise voice over IP (VOIP) data of one or more vocoder rates and packet data of one or more data rates, and the physical layer burst classification comprises identification of the data transmission type carried by a respective data burst as VOIP data or packet data and identification of the respective vocoder rate or data rate on a burst-by-burst basis.
3. The method of claim 2 , wherein the plurality of different data transmission types further comprise keep alive bursts, and the keep alive bursts are transmitted during silence periods of a VOIP session and comprise a minimal number of symbols to minimize transmission power during such silence periods.
4. The method of claim 1 , wherein the uniform format of the first burst type comprises uniform placement of the unique word signature sequence, and the uniform placement of the unique word signature sequence comprises division of the signature sequence into unique word segments and positioning of the segments relative to one another in a manner that offsets channel-induced fading.
5. The method of claim 1 , wherein, in a case where a one of the data bursts of the first burst type carries VOIP data, perceptually important bits and perceptually unimportant bits of the VOIP data are encoded using different FEC coding schemes to improve spectral efficiency, whereby the FEC coding scheme used for the perceptually important bits is of a higher quality target than the FEC coding scheme used for the perceptually unimportant bits.
6. The method of claim 1 , wherein the communications network comprises a satellite communications network configured in a manner whereby two or more satellites operating with polarization diversity are intended to receive the transmission of the data transmission sequence and to transmit the sequence for receipt by at least one target communications device.
7. The method of claim 6 , wherein the uniform format of the first burst type comprises uniform placement of the unique word signature sequence and the uniform placement of the unique word signature sequence comprises a division of the signature sequence into unique word segments and positioning of the segments relative to one another in a manner that offsets one or more of timing, frequency and phase shifts in receipt and transmission of the data transmission sequence between the two or more satellites.
8. The method of claim 6 , wherein, in a case where at least one of the data bursts of the first burst type carries VOIP data, the uniform format of the first burst type comprises an arrangement of the VOIP data in a manner whereby perceptually important bits and perceptually unimportant bits of the VOIP data are arranged relative to each other to minimize voice quality degradation resulting from one or more of timing, frequency and phase shifts in receipt and transmission of the data transmission sequence between the two or more satellites.
9. An apparatus comprising:
a physical layer component configured to generate a data transmission sequence comprising a plurality of data bursts of at least a first burst type, the first burst type being configured to carry a plurality of different data transmission types; and
a transmitter component configured to transmit the data transmission sequence over a dedicated channel of a communications network;
wherein,
the plurality of data bursts includes two or more data bursts of the first burst type respectively carrying at least two different ones of the data transmission types,
each data burst of the first burst type consists of a uniform format irrespective of the data transmission type carried by the data burst,
each data burst of the first burst type comprises a unique word signature sequence that is unique to the data transmission type carried by the data burst providing for physical layer burst classification, and
in a case where a one of the data bursts of the first burst type carries VOIP data, the uniform format of the first burst type comprises an arrangement of the VOIP data in a manner whereby perceptually important bits and perceptually unimportant bits of the VOIP data are arranged relative to each other to maximize interleaving and coding gains in fading channels.
10. The apparatus of claim 9 , wherein the plurality of different data transmission types comprise voice over IP (VOIP) data of one or more vocoder rates and packet data of one or more data rates, and the physical layer burst classification comprises identification of the data transmission type carried by a respective data burst as VOIP data or packet data and identification of the respective vocoder rate or data rate on a burst-by-burst basis.
11. The apparatus of claim 10 , wherein the plurality of different data transmission types further comprise keep alive bursts, and the keep alive bursts are transmitted during silence periods of a VOIP session and comprise a minimal number of symbols to minimize transmission power during such silence periods.
12. The apparatus of claim 9 , wherein the uniform format of the first burst type comprises uniform placement of the unique word signature sequence, and the uniform placement of the unique word signature sequence comprises division of the signature sequence into unique word segments and positioning of the segments relative to one another in a manner that offsets channel-induced fading.
13. The apparatus of claim 9 , wherein, in a case where a one of the data bursts of the first burst type carries VOIP data, perceptually important bits and perceptually unimportant bits of the VOIP data are encoded using different FEC coding schemes to improve spectral efficiency, whereby the FEC coding scheme used for the perceptually important bits is of a higher quality target than the FEC coding scheme used for the perceptually unimportant bits.
14. The apparatus of claim 9 , wherein the communications network comprises a satellite communications network configured in a manner whereby two or more satellites operating with polarization diversity are intended to receive the transmission of the data transmission sequence and to transmit the sequence for receipt by at least one target communications device.
15. The apparatus of claim 14 , wherein the uniform format of the first burst type comprises uniform placement of the unique word signature sequence and the uniform placement of the unique word signature sequence comprises a division of the signature sequence into unique word segments and positioning of the segments relative to one another in a manner that offsets one or more of timing, frequency and phase shifts in receipt and transmission of the data transmission sequence between the two or more satellites.
16. The apparatus of claim 14 , wherein, in a case where at least one of the data bursts of the first burst type carries VOIP data, the uniform format of the first burst type comprises an arrangement of the VOIP data in a manner whereby perceptually important bits and perceptually unimportant bits of the VOIP data are arranged relative to each other to minimize voice quality degradation resulting from one or more of timing, frequency and phase shifts in receipt and transmission of the data transmission sequence between the two or more satellites.