Field of the Invention

This invention relates to a reverse powered wireless distribution point.

Background to the Invention

Providing high speed fixed broadband services such as VDSL2 and G.fast is dependent on minimising the length of the copper pairs between the broadband customer premises equipment (CPE) and the distribution point unit (DPU) where the copper pairs are terminated. Fibre optic cable is typically utilised to connect the DPU to a telephone exchange. Line speeds increase as the length of copper decreases, so there is a move to locate DPUs closer to the customer, moving them from a cabinet to for example poles and even on the external walls of customers’ premises. However, installing new fibre to these locations is costly and time consuming for the network operator or infrastructure provider.

Reverse power feeding (RPF) is a standardised technology (see ETSI TS 101548) that allows power to be sent from CPEs to a DPU in order to power the DPU. This simplifies deployment by removing the power dependency of DPUs. Nonetheless, fibre still needs to be installed from the exchange to the DPU.

Summary of the Invention

It is the aim of examples of the invention to provide a method of operating a distribution point having a high capacity wireless backhaul.

According to one aspect of the present invention, there is provided a method of operating a distribution point unit, the distribution point unit having a wireless backhaul connection and one or more electrically wired access connections to respective customer premises equipment, said distribution point unit being electrically powered by the one or more electrically wired access connections, the method comprising: determining a power available to the distribution point from the one or more electrically wired access connections; and switching the wireless backhaul connection from a first wireless configuration to a second wireless configuration based on the determined power available, wherein the first and second wireless configurations have different power utilisations.

The second wireless configuration may have a power utilisation that is no greater than the available power. The second wireless configuration may have a higher power utilisation than the first wireless configuration. The second wireless configuration may have a lower power utilisation than the first wireless configuration.

The first and second wireless configurations may have different data rates.

The distribution point unit may further comprise a wired backhaul connection, and the power available for the wireless backhaul connection is reduced by the power required by the wired backhaul connection.

According to a further aspect of the present invention, there is provided a distribution point unit having a wireless backhaul connection and one or more electrically wired access connections to respective customer premises equipment, said distribution point unit being electrically powered by the one or more electrically wired access connections and adapted to: determine a power available to the distribution point from the one or more electrically wired access connections; and switch the wireless backhaul connection from a first wireless configuration to a second wireless configuration based on the determined power available, wherein the first and second wireless configurations have different power utilisations.

Examples of the invention provide traditional fixed line copper broadband services (DSL, VDSL, G.fast etc) using the fixed network distribution point, but which is backhauled to the core network using high capacity cellular radio technology. The backhaul capacity is scaled by scaling the radio transceiver capability with the available power that can be obtained from the reverse powered subscriber lines.

Such a solution can result in a more rapid deployment of faster fixed broadband services, which might otherwise be constrained by the fixed backhaul circuit (e.g. the copper line length to the exchange or the economic expense to lay new fibre to the distribution point unit). Utilising reverse powering techniques from the subscriber lines is particularly advantageous as no new power infrastructure is need to power the distribution point unit, and no new fibre or expensive upgrades are needed to improve the broadband speed delivered to the end customer. A fibre backhaul can be installed later to replace the wireless backhaul as necessary.

Brief Description of the Drawings

For a better understanding of the present invention reference will now be made by way of example only to the accompanying drawings, in which:

Figure 1 is a system diagram showing a DSL network with several customer premises connected to a distribution point unit in an example of the invention;

Figure 2 is schematic diagram showing the main components of a distribution point unit in an example of the invention;

Figure 3 is a flow chart summarising the steps of an example of the invention; Figure 4 is a table showing various radio transceiver configurations with their associated capacity and power requirements.

Description of Preferred Embodiments

The present invention is described herein with reference to particular examples. The invention is not, however, limited to such examples.

Examples of the present invention present a method of operating a distribution point unit (DPU) having a wireless backhaul connection, such as a 4G or 5G connection. The distribution point unit is reverse powered electrically by connected subscriber lines. The radio configuration (number of antennas, frequencies, etc) used by the wireless backhaul connection is switched according to the power available from the subscriber lines. Changes to the available power can trigger a switch to a new radio configuration. Higher capacities (data rates) can be achieved with higher power radio configurations, which can be switched over to if the available power is sufficient. Similarly, when the available power drops, a switch can be made to an appropriate lower powered radio configuration.

Figure 1 illustrates a telecommunications network 100 including 3 customer’s premises 102a, 102b and 102c. Each of the customer’s premises 102a, 102b and 102c is connected to a distribution point unit (DPU) 108 via respective telephone lines 104a, 104b and 104c. Each of the telephone lines is a twisted copper or aluminium pair of wires. Specifically, a customer premises equipment 106a, 106b or 106c, connect to the end of each of the lines at the customer premises end.

In this example, the DPU 108 is located on a pole, but could be located elsewhere, such as beneath ground or in a street cabinet. The DPU 108 includes a wireless radio transceivers that provide a wireless backhaul connection to a telephone exchange 112, for example over 4G, 5G or a combination of the two. Note, the physical antenna may be separately located from the DPU for optimal placement, and connected to the DPU via suitable connection such as coaxial cable. The DPU 108 is reverse powered by one or more the connected lines, which are electrically powered by their respective CPE. Similarly, the modem 212 and transceivers can be located separately from the rest of the DPU and connected via a suitable Ethernet connection.

The telephone exchange 112 includes a digital subscriber line access multiplexer (DSLAM), not shown. The DSLAM provides digital subscriber line (DSL) services, such as VDSL or G.fast, to connected lines and associated customer premises.

Figure 2 shows the main components of the DPU 108 in an example of the invention. The DPU 108 comprises the DSL subscriber ports 202, a power management module 204, a processor 206, memory 208, an uplink interface 210, a cellular radio modem 212, and several radio transceivers 214, 216 and 218.

The DSL subscriber port 202 is the interface at which the physical and lower protocol layer logical connections from the customer premises is first aggregated, this is typically a twisted pair phone line.

The power management module 204 is capable of determining the power requirements from all constituent parts of the solution as well as monitoring available power delivered by connecting CPEs. It is capable of determining the minimum operating power required for each port and deriving the residual power budget that could be offered to other circuitry or components.

The processor 206 executes operational processes from all components and performs calculations for determining the optimal radio configuration based on information provided by the power management module 204. The memory 208 stores the persistent operating system/code and configuration files required by the all components and is accessed by the processor 206.

The uplink interface 210 is where a fibre or copper connection is usually established for the backhaul into the core network. In examples of this invention, the uplink interface 210 is routed to (or shared with) the cellular radio modem 212 for onward forwarding of user traffic to the network over a wireless backhaul connection. The cellular radio modem 212 and associated radio transceivers 214, 216 and 218 are responsible for handling the radio protocols and physical radio modulation (respectively) that are necessary for establishing a wireless radio connection to a wider area cellular basestation site (for example, the exchange 112) for connectivity back into the core network. The modem 212 may control multiple transceivers and their configurations for optimal use with particular technologies or radio frequencies, as will be described in examples below.

Figure 3 is a flow chart 300 summarising the steps of operating the DPU 108.

Processing starts at step 302.

In step 304, the power management module 204 determines the initial power available from the connected lines 104a, 104b and 104c. However, some customers may switch off their CPE when not in use, or the CPE might be switched off for some other reason. Power will only be available for reverse powering from the connected lines where the associated CPE is actually online (powered on). The ETSI specification (TS 101548) sets out protocols for signalling the resistivity of the line at start up, which is dependent on the length and quality of the copper line. A class verification function provides DPU and CPE mutual identification, giving a signature classification represented by a specific current level. The CPE can then output up to this maximum current level at an output voltage of up to 60V. The DPU 108 can draw as much power as needed up to the maximum that can be supported by each line as given by the output voltage and maximum current (e.g. 60V DC and 250mA results in supported power of 15VA ~= 15W for that line).

However, not all the supported power from each CPE is available for use by the DPU. Each of the subscriber ports 202 that connect an active (online) subscriber line will draw power in operation. Thus, the initial available power is equal to the sum of the power supported by each line (that is online), minus the power needed to operate the subscriber ports that are online. In step 306, the initial radio configuration is selected based on initial available power.

Figure 4 shows a table 400 of an example of different radio transceiver configurations 402 supported by the DPU 108 and specifically the radio transceivers 214, 216 and 218. The DPU 108 can select and use any one of these configurations, with each configuration 402 having an associated peak capacity (bandwidth) 404 and operating power requirement 406. They range from a simple 4G single-band configuration with a peak capacity of 150Mbps and a power requirement of 3W, to a more complex configurations such as one consisting of a combination of 5G mmWave, 5G multi-band and 4G multiband, which has a peak capacity of well over 1 Gbps and a power requirement of 33W. Referring to Figure 2, each radio configuration might involve use of one or more of the radio transceivers 214, 216 and 218. Thus, switching between radio configurations can involve switching on/off one or more of the transceivers, or extending the operating bandwidth or frequencies over which a transceiver is specified for.

The initial radio configuration that is selected needs to have a power requirement that is less than or equal to the initial available power. Thus, if we take the initial available power across all the connected xDSL ports to be 25W, then the radio configuration selected from the ones shown in table 400 would be the 5g mmWave and 5G multiband configuration, which has a power requirement of 20W and a peak capacity of 1 Gbps. Whilst lower power configurations can also be supported by the initial available power, the configuration with the highest capacity is usually selected in examples of the invention.

Upon completing the start-up procedure whereby the detection, classification and power available from connecting CPEs is determined by the DPU, the DPU processor 206 reads the initial available power calculation available for the radio modem 212 from the power management module 204. Based on this information the processor 206 determines the optimal radio transceiver configuration that can be supported. The processor 206 then writes a suitable modem configuration file to memory 208 and initiates the modem start up procedure. Here the modem 212 is provided power by the power management module 204 and proceeds to read in its configuration file from memory 208 to determine which radio configuration to use. This includes deciding which transceivers 214, 216, 218 and associated radio technologies, frequencies and bandwidths it should scan for and advertise in subsequent connection establishment to the basestation (e.g. at the exchange 112). Once the DPU 108 has an initial radio configuration selected and operational, there follows a continuous monitoring phase, where the reverse power available from the lines is determined in step 308 in the same manner as in step 304 earlier. If there is no change in the available power (step 310), processing continues with determining the available power in step 308 until there is a change in available power. Once there is a change in the available power in step 310, processing passes to step 312.

At step 312, a check is made to determine if the available power (from step 308) is sufficient to support current radio configuration. As might be the case sometimes, the available power may have dropped since the DPU 108 was started up and the initial radio configuration selected, so that the available power might no longer be sufficient to support the initial radio configuration. This might happen if one or more of the CPEs is switched off following start up, thus depriving the DPU of some reverse power.

If there is no longer sufficient available power to support the current radio configuration, then processing passes to step 314.

In step 314, a new radio configuration based on the available power is determined. This is done like in step 306 by looking for the highest capacity radio configuration that has a power requirement that is less than or equal to the available power. The configuration details are written to an updated configuration file and stored in memory 208.

In step 316, a switch is made to the new radio configuration, before processing passes back to the monitoring phase starting at step 308.

The switching to a new radio configuration involves the cellular radio modem 212 releasing the connection to the cellular basestation(s) it is connected to, and restarting its connection establishment procedure using the updated configuration file. In practice, the DPU 108 can also include a battery back-up, which can hold sufficient power to support any given radio configuration for a period of time after a drop in available power, and before the switch to a new radio configuration has completed. This provides a more graceful switch to a new radio configuration. In the absence of a battery back-up of similar, the DPU 108 would be forced to power down one or more of the radio transceivers immediately to reduce power consumption. Some traffic would be temporarily lost in such an event until higher layer protocols stabilise the connection on the remaining resources available.

However, if in step 312 it is determined that the available power is sufficient to support the current radio configuration, processing passes to step 318.

In step 318, a check is made to determine if there is a higher rate (than the current rate) radio configuration that can be supported by the available power. This might occur if the available power increases, for example if previously offline CPEs are brought back online thus providing additional reverse power.

If a higher rate can be supported, then processing passes to step 314, which determines which higher rate radio configuration can be supported before making the switch in step 316. These steps are as described earlier above. Processing then passes back to the monitoring phase of step 308.

To illustrate, if the available power changes from 25W to 35W, then there is sufficient power to support the highest rate radio configuration of 5g mmWave, 5G multiband and 4G multiband, which has a peak capacity of over 1 Gbps.

If in step 318 it is determined that a higher rate cannot be supported, then processing passes back to continuous monitoring starting at step 308.

In another example of the invention, the backhaul connection is provided over a hybrid wired and wireless backhaul connection. The wired connection could be fibre or copper for example, as in a typical ADSL or VDSL/G.fast arrangement. However, a wireless backhaul is also provided as described above. The wireless backhaul can be used for load sharing, or as a failover option if the wired backhaul connection fails.

In such a hybrid arrangement, the available power from the reverse powering will need to be shared between the wired and wireless backhaul connections. Thus, instead available power for the wireless radio configuration will be reduced by the power required by the wired connection, before the wireless radio configuration can be determined (in step 314).

Exemplary embodiments of the invention are realised, at least in part, by executable computer program code which may be embodied in an application program data. When such computer program code is loaded into the memory 208 of the DPU 108, it provides a computer program code structure which is capable of performing at least part of the methods in accordance with the above described exemplary embodiments of the invention.

A person skilled in the art will appreciate that the computer program structure referred can correspond to the flow chart shown in Figures 3, where each step of the flow chart can correspond to at least one line of computer program code and that such, in combination with the processor 206 in the DPU 108, provides apparatus for effecting the described process.

In general, it is noted herein that while the above describes examples of the invention, there are several variations and modifications which may be made to the described examples without departing from the scope of the present invention as defined in the appended claims. One skilled in the art will recognise modifications to the described examples.