Method and Apparatus for Communication Using a DECT Communication Protocol

Abstract

A method and apparatus e.g. a headset or a base station for controlling channel selection in a communications system (400) using a DECT communications protocol, wherein multiple predefined channels are established using multiple carrier signals at respective carrier frequencies (F1, F2, . . . F8); comprising: transmitting (205) a first signal (S1) on multiple of the channels using automatic channel selection; transmitting a first signal and a second signal on multiple of the channels using automatic channel selection; setting a power level of carrier signals in a first group of channels to a first power level and setting a power level of carrier signals in a second group of channels to a second power level; wherein the second power level is preferably/deliberately set to a predetermined power level higher than the first power level. Wherein the first signal is transmitted in accordance with a first transmission scheme, wherein channel selection is restricted to the channels in the first group of channels, and the second signal is transmitted in accordance with the second transmission scheme, wherein channel selection is restricted to the channels in the second group of channels.

Claims

1-15 (canceled).

16. A method of controlling automatic channel selection in a wireless communications system while minimizing channel interference, using a frequency division communications protocol, wherein predefined channels are established using multiple carrier signals at respective carrier frequencies comprising: transmitting a first signal on one or more of the channels using automatic channel selection; configuring a power level of carrier signals and assigning power levels to users, without regard to user location, a first group of channels for a first power level and configuring a power level of carrier signals in a second group of channels for a second power level; wherein the second power level is deliberately higher than the first power level; and receiving settings that assign signals, devices or users to: a first group, permitted to use exclusively the first transmission scheme, a second group, permitted to use exclusively the second transmission scheme, a third group, permitted to use a combination of the first and second transmission scheme; wherein automatic channel selection, is performed in accordance with the received settings; wherein the first signal is transmitted in accordance with a first transmission scheme, wherein automatic channel selection is restricted to the channels in the first group of channels, and/or in accordance with the second transmission scheme, wherein automatic channel selection is restricted to the channels in the second group of channels.

17. A method according to claim 16, comprising: at least for a predetermined period of time, for a group of units or users, restricting the first signal or a group of signals for transmission in accordance with the first transmission scheme.

18. A method according to claim 16, wherein the first signal is branched into the second branch temporarily and when branching commences the first signal is redirected from the first branch to the second branch, while the first branch is kept alive wherein header information is transmitted on the first branch without a data payload.

19. A method according to claim 16, comprising: branching the first signal into a first branch signal and into a second branch signal; wherein the first branch signal and the second branch signal are transmitted in parallel in accordance with the first transmission scheme and in accordance with the second transmission scheme, respectively.

20. A method according to claim 16, comprising: shifting a transmission of the first signal from being transmitted in accordance with the first transmission scheme to be transmitted in accordance with the second transmission scheme, or vice versa.

21. A method according to claim 16, comprising: measuring values of a signal quality indicator for each of the multiple channels; in respect of the first signal being transmitted on a current channel in accordance with the first transmission scheme and in connection with deciding on selecting another channel in the first transmission scheme: shifting transmission of the signal from the first transmission scheme to the second transmission scheme in case measured values of a signal quality indicator indicates that other channels in the first transmission scheme yields a signal quality below a predefined threshold.

22. A method according to claim 16, comprising: measuring values of a signal quality indicator for each of the multiple channels; in respect of the first signal, determining a trend in the measured values of the signal quality indicator; and shifting transmission of the first signal from the first transmission scheme to the second transmission scheme, in case the trend is going towards or below a poorer signal quality level than measured for any other channel among the channels under the first transmission scheme.

23. A method according to claim 16, comprising: shifting the transmission of the first signal from the first transmission scheme to the second transmission scheme, or vice versa; wherein shifting the transmission comprises starting transmission on the second transmission scheme and stopping transmission on the first transmission scheme, or vice versa.

24. A method according to claim 16, comprising: shifting transmission from the first transmission scheme to the second transmission scheme or vice versa; and wherein shifting the transmission comprises starting transmission on the second transmission scheme; continuing transmission on the first transmission scheme.

25. A method according to claim 16, wherein, at a base station, the first signal is branched into the second branch temporarily and when branching commences the first signal is redirected from the first branch to the second branch, while the first branch is kept alive by header information is transmitted on the first branch without a data payload; and wherein, at a headset which is roaming, the headset stops transmitting on low power channels comprised by the first transmission scheme.

26. An apparatus configured communicate in accordance with a frequency division communications protocol and to control automatic channel selection while minimizing channel interference, wherein the apparatus is configured to transmit respective carrier signals at respective carrier frequencies and predefined channels to user devices; comprising: a transceiver configured to transmit a first signal on at least one of the predefined channels using automatic channel selection; wherein the transceiver is configured to transmit carrier signals in a first group of channels at a first power level and to transmit carrier signals in a second group of channels at a second power level; wherein the second power level is deliberately higher than the first power level; wherein the apparatus is configured to receive signal settings that assign signals and user devices to: a first group, permitted to use exclusively a first transmission scheme, a second group, permitted to use exclusively a second transmission scheme, a third group, permitted to use a combination of the first and second transmission scheme; wherein said transceiver is configured to a assign power level of carrier signals and assign power levels to user devices, without regard to user location to, a first group of channels assigned to a first power level and a second group of channels assigned to a second power level; wherein the second power level is deliberately higher than the first power level; and wherein automatic channel selection, is performed in accordance with the received signal settings; wherein automatic channel selection is performed in accordance with the received settings; wherein the transceiver is configured to transmit the first signal in accordance with a first transmission scheme, wherein channel selection is restricted to the channels in the first group, and to transmit the first signal in accordance with the second transmission scheme, wherein channel selection is restricted to the channels in the second group of channels.

27. A method of controlling automatic channel selection in a communications system using a frequency division communications protocol, wherein predefined channels are established using multiple carrier signals at respective carrier frequencies comprising: transmitting a first signal on one or more of the channels using automatic channel selection; configuring a power level of carrier signals and assigning power levels to users, without regard to user location, to a first group of channels for a first power level and configuring a power level of carrier signals in a second group of channels for a second power level; wherein the second power level is deliberately higher than the first power level; and receiving settings that assign signals, devices or users to: a first group, permitted to use exclusively the first transmission scheme, a second group, permitted to use exclusively the second transmission scheme, a third group, permitted to use a combination of the first and second transmission scheme; wherein automatic channel selection, is performed in accordance with the received settings; wherein the first signal is transmitted in accordance with a first transmission scheme, wherein automatic channel selection is restricted to the channels in the first group of channels, and in accordance with the second transmission scheme, wherein channel selection is restricted to the channels in the second group of channels; branching the first signal into a first branch signal and into a second branch signal; wherein the first branch signal and the second branch signal are transmitted in parallel in accordance with the first transmission scheme and in accordance with the second transmission scheme, respectively.

28. A method according to claim 27, using a DECT communications protocol.

29. A method according to claim 27, wherein the first group of channels is transmitted in first time slots and wherein the second group of channels is transmitted in second time slots; wherein the first time slots and the second time slots are mutually exclusive.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0088] A more detailed description follows below with reference to the drawing, in which:

[0089] FIG. 1 shows a block diagram of a unit in a first embodiment with a first and a second transmission scheme;

[0090] FIG. 2 shows a flowchart for a method of controlling channel selection;

[0091] FIG. 3 shows a transmission spectrum for the first and second transmission scheme;

[0092] FIG. 4 shows a headset and a base station; and

[0093] FIG. 5 shows a block diagram of a unit in a second embodiment with a first and a second transmission scheme.

DETAILED DESCRIPTION

[0094] FIG. 1 shows a block diagram of a unit in a first embodiment with a first and a second transmission scheme. In the first embodiment, the unit 100 comprises a first transmitter 102 and a second transmitter 103 that uses respective groups of carrier signals to transmit a signal, S1, such as a voice signal or a data signal, as a wireless signal via an antenna 104.

[0095] A carrier signal of the first transmitter 102 is generated by modulator MOD-A, 109, and is amplified by a radio frequency amplifier 111. The power level at which the carrier signal is transmitted is set by power unit PWR-A, 117, and is denoted a first power level.

[0096] Likewise, for the second transmitter 103, a carrier signal of the second transmitter 103 is generated by modulator MOD-B, 115, and amplified by a radio frequency amplifier 116. The power level at which the carrier signal of the second transmitter is transmitted is set by power unit PWR-B, 119, and is denoted a second power level. The second power level is higher than the first power level. So the carrier signal from the second transmitter is stronger than the carrier signal from the first transmitter. The second power level is e.g. higher than 13 dBm1 dBm e.g. 20 dBm1 dBm or 23 dBm1 dBm, whereas the first power level is lower than 10 dBm1 dBm e.g. 6 dBm1 dBm or 0 dBm. The second power level is higher than the first power level by more than 3 dBm1dBm e.g. by more than 6 dB1 dB, or more than 10 dB1 dB, or more than 13 dB1 dB or more than 20 dB1 dB.

[0097] The frequencies of the respective carrier signals are synthesized by respective frequency synthesizers 110 and 114 which synthesize a frequency selected by channel selector A, 112, and channel selector B, 113, respectively. As shown, channel selector A, 112, is restricted by a channel group organizing unit 118 to select a frequency channel among the channels 1 through 5. In a similar manner, channel selector B, 113, is restricted by the channel group organizing unit 118 to select a frequency channel among the channels 6 through 8. Alternatively, other channel groups can be set and/or fewer or more than 8 channels may be available. In this embodiment, the channel group organizer 118 thus assigns available channels 1 through 8 to either the first transmitter 102 or the second transmitter 103 in a mutually exclusive manner i.e. a channel is assigned to be transmitted either at high power or at low power; not both. The modulators 109 and 115 may be FDMA modulators.

[0098] With the above described configuration of the unit 100, the signal S1 is input to the modulator A, 109, via a signal SB1 of the first transmitter 102 and to the modulator B, 115, via a signal SB2 of the second transmitter 103 via a modulator MOD, 101. The modulator 101 may be a TDMA modulator. By means of time-division modulation, the signal S1 is transmitted in allocated time slots or simply slots. The allocated slots are selected in a conventional way known in the art such that interference with signals from other transmitters is avoided. A controller 108 may be used for this and/or other purposes. Thus the first transmitter 102 and the second transmitter 103 implements the first transmission scheme and the second transmission scheme, respectively.

[0099] The controller 108 may also be configured in combination with channel group organizing unit 118 to restrict the first signal, S1, or a group of signals for transmission by means of the first transmitter 102 in accordance with the first transmission scheme. Also controller 108 may be configured to restrict the first signal or a group of signals for transmission by means of the second transmitter 103 in accordance with the second transmission scheme.

[0100] In some embodiments the controller 108 is configured to receiving settings that assign signals, devices or users to: 1) a first group, permitted to use exclusively the first transmission scheme, or 2) a second group, permitted to use exclusively the second transmission scheme, or 3) a third group, permitted to use a combination of the first and second transmission scheme.

[0101] The controller may then perform channel selection, during transmission of signals respective devices or users, in accordance with the received settings. The controller 108 may be configured to receive the settings from an Intranet or Internet server or another system wherefrom settings can be administrated. Such configurations are known in the art.

[0102] The signal S1 may be transmitted simultaneously or in parallel by both the first transmitter 102 and the second transmitter 103. Thus, the controller 108 or the configuration of the unit 100 may enable branching of the first signal, S1, assigned to a user, into the first branch signal, SB1, and into a second branch signal, SB2; wherein the first branch signal and the second branch signal are transmitted in parallel in accordance with the first transmission scheme and in accordance with the second transmission scheme, respectively.

[0103] The controller may shift a transmission of the first signal from being transmitted as the first signal in accordance with the first transmission scheme to be transmitted in accordance with the second transmission scheme, or vice versa.

[0104] It should be noted that the signal S1 may be allocated to some time-slots in the signal SB1 and to other time-slots in the signal SB2.

[0105] A person skilled in the art will recognize various ways of implementing the above. Also, the person skilled in the art will recognize how to receive signals e.g. to implement a listen-before-talk technique and/or to compute an indicator of received signal strength e.g. the so-called Received Signal Strength Indicator abbreviated RSSI. The unit 100 may thus comprise receiving signals via amplifier 105 that is coupled to receive signals via the antenna 104, to demodulate the signals by demodulator 106 and compute an indicator of: ongoing transmissions among remote transmitters and receivers (to implement a listen-before-talk technique), interference, and/or signal strength.

[0106] An explicated description of the channel selection in connection with time-division and frequency-division modulation is given below, with reference to table 1 and similarly structured tables below, wherein each row represents a frequency channel and wherein each column represents a timeslot. The tables show exemplary values of RSSI in dBm for respective channels and timeslots.

[0107] With reference thereto, in a first example, channel and slot selection is performed by the FP. The FP continuously monitors the RSSI, which may appear as shown below in table 1:

TABLE-US-00001 TABLE 1 RSSI [dBm] per channel and slot Chan- Slot nel 1 2 3 4 5 . . . 13 14 15 1 70 66 69 65 68 70 66 69 2 80 50* 71 73 66 80 xx 71 3 71 63 70 58 67 71 63 70 4 60 80 80 66 57 60 80 80 5 65 65 71 67 79 65 65 71 6 77 75 60 77 80 77 75 60 7 70 63 33 80 40 44 63 33 8 66 44 60 66 44 55 44 60

[0108] Table 1 shows a snapshot of a RSSI measurement. In this example it is assumed that frequency channels 1 to 6 are assigned to a low power group while channels 7 and 8 are assigned to a high power group.

[0109] The snapshot in table 1, illustrates that the FP currently transmits in slot 14 of channel 2 (shown by xx) and receives in slot 2 of channel 2 (shown by *) while the PP, correspondingly, transmits in slot 2 and receives in slot 14, of channel 2.

[0110] The FP constantly monitors the RSSI of its PP (channel 2 slot 2). If the RSSI of the PP drops below a certain limit the FP will conclude that the user is on the go (e.g. walking towards a more remote position) and it will look for an available channel and slot in the high power channel group. If a high power channel and slot is found, the FP will instruct the PP and perform the switch.

[0111] The RSSI threshold at which the FP will start the group transition may be fixed. It could be selectable by the user or under control of a system administrator e.g. via an Intranet or Internet server.

[0112] The RSSI could also be adaptive. The FP then dynamically analyses the RSSI values of all slots and channels in the low power group in order to deduct a background noise level and then set a roaming threshold relative to the background RSSI level. The background RSSI level is e.g. computed as the mean of the n lowest RSSI measurements of any channel/slot combination; wherein n is an index value.

[0113] When the FP decides to transition to the high power group, the FP preferably continues to transmit in the currently allocated channel and slot in the low power group. In this way it will assure that its low power channel and slot will still be available when the headset user returns to a closer position (e.g. his office chair) because other units will stay away from the channel/slot while it is in use. The FP may however also decide to stop the transmission in the low power group while it is transmitting in the high power group.

[0114] Once the unit has switched to roaming state and transmits in the high power channel group it will want to monitor the RSSI measurement in order to establish whether to return to the low power channel group. The FP can again set a threshold on the RSSI measurement for the slot where its PP is transmitting. When this RSSI value exceeds a predefined limit it is indicator that the PP is close to the FP and that the unit can switch to the low frequency group and stop transmitting in the high power group.

[0115] Turning to table 2 and 3 below, snapshots of RSSI measurements taken while the unit is transmitting in the high power groups are shown.

[0116] If the RSSI threshold in the roaming mode for example was set to 30 dBm then the RSSI in table 2 would indicate that the unit should stay in the high power group while the RSSI of table 3 would indicate that the unit should transition to the low power group.

TABLE-US-00002 TABLE 2 RSSI [dBm] per channel and slot Slot Channel 1 2 3 4 5 . . . 13 14 15 1 70 66 69 65 68 70 66 69 2 80 .sup.80(*) 71 73 66 80 xx 71 3 71 63 70 58 67 71 63 70 4 60 80 80 66 57 60 80 80 5 65 65 71 67 79 65 65 71 6 77 75 60 77 80 77 75 60 7 70 63 33 80 40 44 63 33 8 66 44 40* 66 44 55 44 xx

TABLE-US-00003 TABLE 3 RSSI [dBm] per channel and slot Slot Channel 1 2 3 4 5 . . . 13 14 15 1 70 66 69 65 68 70 66 69 2 80 .sup.80(*) 71 73 66 80 xx 71 3 71 63 70 58 67 71 63 70 4 60 80 80 66 57 60 80 80 5 65 65 71 67 79 65 65 71 6 77 75 60 77 80 77 75 60 7 70 63 33 80 40 44 63 33 8 66 44 20* 66 44 55 44 xx

[0117] In table 2 and 3 above it is assumed that the FP continues to transmit in the low power group while it utilizes the high power group for the actual signal/data transmission, however this need not be the case in all embodiments.

[0118] The unit may be a fixed point (FP) or a portable point (PP). The unit may be a headset or a headset base station or a telephone handset or a telephone handset base station or another type of unit.

[0119] FIG. 2 shows a flowchart for a method of controlling channel selection. The method is performed by a unit such as a radio transmitter or the transmitter portion of a radio transceiver.

[0120] In a first step 201 a signal S1 is received by the radio transmitter. In case the transmitter is embodied in a headset, the signal S1 is received e.g. from an audio signal processor (not shown) and an encoder (not shown) that in combination converts a signal from a microphone configured to pick up a user's voice to a digital signal that can be transmitted wirelessly. In case the transmitter is embodied in a headset base station, the signal S1 is received e.g. from the switched public telephone network (PSTN) and/or the Internet.

[0121] Optionally, the method may comprise step 207 receiving settings e.g. from an Intranet server and/or from a user interface of the headset base station that assign signals, devices or users to 1) a first group, permitted to use exclusively the first transmission scheme, or 2) a second group, permitted to use exclusively the second transmission scheme, or 3) a third group, permitted to use a combination of the first and second transmission scheme.

[0122] Based on the received settings or from otherwise configured settings, a transmission scheme for the signal S1 is selected in step 202. A transmission scheme is selected from a group comprising a first transmission scheme and a second transmission scheme. In accordance with the first transmission scheme channel selection is restricted to channels among a first group of channels; and in accordance with the second transmission scheme, channel selection is restricted to channels among a second group of channels.

[0123] Step 203 comprises configuring and/or setting a power level of carrier signals in the first group of channels for the first power level and configuring and/or setting a power level of carrier signals in the second group of channels for a second power level. The configuration of a power level may be implemented by a hardware configuration or by a hardware configuration operating under control of a programme run by a processor.

[0124] In step 204 transmission of signal S1 is performed in accordance with the selected transmission scheme and thus at the respective power level.

[0125] This transmission, in accordance with the selected transmission scheme, continues until the transmission is terminated (e.g. in response to a call being terminated).

[0126] However, the method may involve measuring values of a signal quality indicator e.g. RSSI for each of the multiple channels and then the transmission scheme may be changed from the first transmission scheme to the second transmission scheme for an ongoing transmission in case values of the signal quality indicator drops below a threshold. The reverse situation may also occur, e.g. that an ongoing transmission takes place in accordance with the second transmission scheme and then that the value of the signal quality indicator is above a threshold; which makes it possible to change to the first (low power) transmission scheme.

[0127] RSSI or another signal quality measure is measured or computed in step 205. A threshold for determining at what level of the signal quality level indicator to change transmission scheme is determined in step 206. In combination therewith or additionally, a trend of values for determining when to change transmission scheme is determined.

[0128] Based on an evaluation of values of the signal quality indicator against the threshold, the transmission scheme may be changed in step 208. That is, in case measured values of the signal quality indicator indicates that other channels in the first transmission scheme yields a signal quality below a predefined threshold, step 208 shifts transmission of the first signal from the first transmission scheme to the second transmission scheme.

[0129] Various other embodiments of the setting power levels and selecting a transmission scheme can be foreseen.

[0130] FIG. 3 shows a transmission spectrum for the first and second transmission scheme. The transmission spectrum is shown in diagram wherein the abscissa axis represents frequency, f [Hz], and wherein the ordinate axis represents transmitted power, P [dBm].

[0131] The transmission spectrum 300 shows a distribution of multiple carrier spectrums each designated 303, for respective carrier signals at a first power level P1, 301, and at centre frequencies F1 through F5. The transmission spectrum 300 also shows multiple carrier spectrums, each designated 304, for respective carrier signals at a second power level P2, 302, and at centre frequencies F6, F7 and F8.

[0132] A first group of channels, 305, is transmitted using one or more of the carrier signals in a first group GR-A, 308 of carrier signals transmitted at the first power level, P1. A second group of channels, 306, is transmitted using one or more of the carrier signals in a second group GR-B, 309, of carrier signals 309 transmitted at the second power level, P2. The first group of channels 305 and the second group of channels 306 are shown by dashed lines since the channels are not directly physical signals.

[0133] FBAND, 307, designates a frequency band within which the signals are distributed. FBAND may be located in the so-called 1.9 Ghz band i.e. slightly above or below 1.9 Ghz e.g. 1.9 GHz10% or at another frequency.

[0134] FIG. 4 shows a headset and a base station. The headsetsometimes denoted the portable part, PPis in general designated 403 and comprises a headband 406 with a support 407, an earpiece 408 with a loudspeaker or speaker (not shown), and a microphone boom 409 with a microphone (not shown). The headset 403 additionally comprises a wireless transceiver (not shown) for communicating wirelessly, as illustrated by dashed line 405, with the headset base station 402sometimes denoted the fixed part, FP.

[0135] The headset base station 402 comprises a wireless transceiver for communicating with the headset e.g. in accordance with the DECT standard. The headset base station 402 is coupled by a wired or wireless connection 404 to a communications network 401. The communications network 401 may comprise the Publicly Switched Telephone Network (PSTN), the Internet, an Intranet or any combination thereof.

[0136] The above represents an exemplary system 400, wherein channel selection using the first transmission scheme and the second transmission scheme can be implemented.

[0137] FIG. 5 shows a block diagram of a unit in a second embodiment with a first and a second transmission scheme. In this second embodiment a unit 123 is configured with a single transmitter 124 that selectively transmits the first signal, S1, in accordance with the first transmission scheme and/or the second transmission scheme.

[0138] A carrier signal for the transmitter 124 is generated by the modulator 109 and amplified by amplifier 111. The power level at which a carrier signal is transmitted is set by power unit 122. In this embodiment the power unit 122 is controlled by a channel selector 120 to transmit at a power level, be it a first (lower) power level or a second (higher) power level.

[0139] The frequency of a carrier signal is synthesized by the frequency synthesizer 110 which synthesize a frequency selected by channel selector AB, 120.

[0140] As shown channel selector AB, 120, selects a frequency channel among the channels 1 through 8. i.e. among all the available frequencies (channels). In this embodiment, a channel group organizer 121 thus assigns all available channels 1 through 8 to the first transmitter 124.

[0141] With the above described configuration of the unit 100, the signal S1 is input to the modulator, 109 via a time-division modulator 101. The time-division modulator 101 may be a TDMA modulator. By means of time-division modulation, the signal S1 is transmitted in allocated time slots or simply slots.

[0142] As shown a control path 125 connects the channel selector AB, 120 with the power unit 122. By means of the control path 125, the power unit is provided with a signal indicative of whether one or more currently synthesized carrier signals is to be transmitted at a first power level or a second power level, or at any other selected power level. The power unit responds to this signal and transmits a carrier signal at an appropriate power level. Thereby, a power level of carrier signals in a first group of channels is set to a first power level and a power level of carrier signals in a second group of channels is set to a second power level.

[0143] The channel selector AB, 120, controls that the first signal, S1, is transmitted in accordance with the first transmission scheme, wherein channel selection is restricted to the channels in the first group of channels (G1), and/or in accordance with the second transmission scheme, wherein channel selection is restricted to the channels in the second group of channels (G2).

[0144] The control path 125 may by controlled by controller 108.

[0145] The receiver portion with amplifier 105, demodulator 106 and processor 107 computing the RSSI indicator is described above. Also, the controller 108 is described above and is configured for this single transmitter embodiment.

[0146] Some embodiments comprises a method of controlling channel selection in a communications system 400 using a frequency division communications protocol, wherein predefined channels are established using multiple carrier signals at respective carrier frequencies; comprising: transmitting 205 a first signal, S1, on one or more of the channels using automatic channel selection; configuring 203 a power level of carrier signals in a first group of channels 308 for a first power level 301 and configuring a power level of carrier signals in a second group of channels 309 for a second power level 302; wherein the second power 302 level is deliberately higher than the first power level 301; wherein the first signal, S1, is transmitted in accordance with a first transmission scheme, TS-A, wherein channel selection is restricted to the channels in the first group of channels 308, and/or in accordance with the second transmission scheme, TS-B, wherein channel selection is restricted to the channels in the second group of channels 309; and branching the first signal, S1, into a first branch signal, SB1, and into a second branch signal, SB2; wherein the first branch signal and the second branch signal are transmitted in parallel in accordance with the first transmission scheme and in accordance with the second transmission scheme, respectively.

[0147] In some aspects of the method, it uses a DECT communications protocol.

[0148] In some aspects of the method, the first group of channels is transmitted in first time slots and wherein the second group of channels is transmitted in second time slots; wherein the first time slots and the second time slots are mutually exclusive.