Wideband-narrowband telecommunication
Here is described a method, a near end telecommunications terminal and a computer executable software code which allow to perform a telecommunications with a far end telecommunications terminal providing the option of applying a narrowband encoding technique without loosing the benefit of a wideband encoding technique. This is achieved after setting up a telecommunications between that near end telecommunications terminal and the far end telecommunications terminal by applying by the codec from the near end telecommunications terminal a sampling when encoding corresponding to a wideband encoding technique while assembling the resulting timeslots into frames to be transmitted to the far end telecommunications terminal via RTP. Furthermore, the sampled timeslots are assembled when applying the wideband encoding technique according to the parity of the sequential integer number from the sampled timeslots to generate two kind of frames, one with all the timeslots identified by even sequential numbers, the other one with the remaining timeslots identified by odd sequential numbers.
1. A method for providing telecommunications between a near end and at least a far end telecommunications terminal, each telecommunications terminal having a codec, the method comprising:
setting up telecommunications between the near end telecommunications terminal and the far end telecommunications terminal;
applying a wideband encoding technique codec at the near end telecommunications terminal to sampled timeslots;
assembling the sampled timeslots when applying the wideband encoding technique according to the parity of their sequential integer number to generate two kinds of Real Time Protocol (RTP) frames to be transmitted to the far end telecommunications terminal via a packet switched network using Real Time Protocol, one with all the timeslots identified by even sequential numbers, the other one with the remaining timeslots identified by odd sequential numbers;
transmitting to the far end telecommunications terminal each of the two kinds of RTP frames via a different specific RTP stream corresponding to a narrowband channel, the two kinds of RTP frames having timestamps related to each other using the same reference clock, wherein each timestamp relates to the mean value of the RTP frame payload time of a RTP frame of the first kind and a RTP frame of the second kind; and
if applying a wideband decoding technique at reception of the two kinds of RTP frames, then reassembling the timeslots according to the initial sequence.
2. The method according to claim 1 wherein the two different RTP streams are identified by the same destination address but different ports of the far end telecommunications terminal.
3. The method according to claim 1 wherein the wideband encoding and decoding technique corresponds to the standardized G.711 with a sampling rate greater than 8 kHz.
4. The method according to claim 1 further comprising setting up telecommunications for a teleconference with more than two telecommunications terminals not all applying the wideband encoding and decoding technique.
5. The method according to claim 4 wherein the teleconference includes a telecommunications terminal applying a narrowband decoding technique utilizing only one of the two kinds of RTP frames.
6. A near end telecommunications terminal comprising: a codec applying a wideband encoding technique for telecommunication between the near end telecommunications terminal and at least a far end telecommunications terminal, wherein the codec, while encoding assembling sampled timeslots into frames to be transmitted to the far end telecommunications terminal via a packet switched network using Real Time Protocol (RTP), assembles the sampled timeslots according to the parity of their sequential integer number to generate two kinds of RTP frames, one kind of RTP frame with all the timeslots identified by even sequential numbers, the other kind of RTP frame with the remaining timeslots identified by odd sequential numbers, the two kinds of frames having timestamps related to each other using the same reference clock, wherein each timestamp relates to the mean value of the RTP frame payload time of a RTP frame of the first kind and a RTP frame of the second kind, wherein the near end telecommunications terminal transmits to the far end telecommunications terminal each of the two kinds of RTP frames via a different specific RTP stream each corresponding to a narrowband channel.
7. The near end telecommunications terminal according to claim 6 wherein the near end terminal reassembles the timeslots according to an initial sequence when applying a wideband decoding technique at reception of the two kinds of RTP frames transmitted from the far end telecommunications terminal which assembled the sampled timeslots according to the parity of the sequential integer number generating the two kinds of RTP frames.
8. The near end telecommunications terminal according to claim 6 wherein the two different RTP streams are identified by same destination address but different ports of the far end telecommunications terminal.
9. The near end telecommunications terminal according to claim 6 wherein the near end terminal applies the wideband encoding and decoding technique according to the standardized G.711 with a sampling rate greater than 8 kHz.
10. A computer executable software code stored on a non-transitory computer readable medium to be executed by a codec at a near end telecommunication terminal for communicating with a telecommunication network with at least a far end telecommunications terminal by applying a wideband encoding technique, wherein the code comprises code for assembling sampled timeslots according to the parity of their sequential integer number to generate two kinds of Real Time Protocol (RTP) frames to be transmitted to the far end telecommunications terminal via a packet switched network using Real Time Protocol, one kind of RTP frame with all the timeslots identified by even sequential numbers, the other one kind of RTP frame with the remaining timeslots identified by odd sequential numbers, each kind of RTP frame having a timestamp related to the other kind of RTP frame using the same reference clock and code for transmitting both kinds of RTP frames to the far end telecommunications via different specific RTP streams each corresponding to a narrowband channel, wherein each timestamp relates to the mean value of the RTP frame payload time of a RTP frame of the first kind and a RTP frame of the second kind.
11. The computer executable software according to claim 10 further comprising the two different RTP streams being identified by same destination address but different ports of the far end telecommunications terminal.
12. The computer executable software according to claim 10 wherein the software code is executed by the codec to form a teleconference between the near end telecommunications terminal and more than one far end telecommunications terminal by transmitting to all of the far end terminals the two kinds of frames independently of the encoding and decoding technique applied by the codec from the far end telecommunications terminals.