Patent Description:
The disclosure relates generally to telecommunications and, more particularly (although not necessarily exclusively), to joint management and optimization of a radio access network and a distributed antenna system.

A distributed antenna system (DAS) can include one or more head-end units and multiple remote units coupled to each head-end unit. A DAS can be used to extend wireless coverage in an area. Head-end units can be connected to one or more base stations of a radio access network (RAN). Each base station can be part of a separate node of the RAN. A head-end unit can receive downlink signals from the base station and distribute downlink signals in analog or digital format to one or more remote units. The remote units can transmit the downlink signals to user equipment devices within coverage areas serviced by the remote units. In the uplink direction, signals from user equipment devices may be received by the remote units. The remote units can transmit the uplink signals received from user equipment devices to a head-end unit. The head-end unit can transmit uplink signals to the serving base stations. The DAS may thus provide coverage extension for communication signals from the RAN nodes.

The RAN and DAS may be separately managed and optimized via respective operations and management self-optimizing network (SON) units. A DAS SON unit, for example, can use parameters and counters specific to the DAS. The DAS SON unit can be fully separated from the RAN equipment. The result of a separate DAS SON unit from RAN equipment is that any modification to the configuration of the RAN nodes can have an unexpected impact on the operation of the DAS. Similarly, any modification to the configuration of the DAS can have an unexpected impact on the RAN nodes. RAN and DAS system optimization cannot be jointly performed on DAS and RAN nodes with a DAS SON unit separated from the RAN nodes. <CIT>, relates to systems and methods for optimized telecommunications distribution. For example, a distributed antenna system can include a master unit for transceiving signals with remote units operable for wirelessly transceiving signals with mobile devices in a coverage area. A self-optimized network analyzer can be in a unit of the distributed antenna system. A self-optimized network controller in the distributed antenna system can output commands for changing operation of a component in the distributed antenna system in response to analysis results from the self-optimized network analyzer. <CIT>, relates to systems and methods for developing a configuration plan for communication transport links of a distributed antenna system. The distributed antenna system includes a unit communicating with remote antenna units over the communication transport links. The unit receives signals from base stations. Characteristics of each of the signals are determined. The characteristics include, for each signal, a frequency occupancy, a digital bandwidth, and a coverage zone to which to provide the signal. The frequency occupancy includes the minimum frequency component and the maximum frequency component of the signal. The digital bandwidth is a bandwidth for communicating the signal via the communication transport links. A hardware capability of the distributed antenna system, such as a respective available bandwidth for each communication transport link, is also determined. The configuration plan for transporting the digital representations of the signals is determined based on the hardware capability and the characteristics of the signals
<CIT>, relates to a configuration sub-system for telecommunication systems. The configuration sub-system can include a test signal generator, a power measurement device, at least one additional power measurement device, and a controller. The test signal generator can be integrated into components of a telecommunication system. The test signal generator can provide a test signal to a signal path of the telecommunication system. The power measurement device and the additional power measurement device can respectively be integrated into different components of the telecommunication system. The power measurement device and the additional power measurement device can respectively measure the power of the test signal at different measurement points in the signal path. The controller can normalize signals transmitted via the telecommunication system by adjusting a path gain for the signal path based on measurements from the power measurement device and the additional power measurement device.

In accordance with an aspect of the invention there is provided a telecommunications system as defined in the appended claims.

Certain aspects and features are directed to methods and systems for jointly managing and optimizing the operation and configuration of a distributed antenna system (DAS) and a radio access network (RAN). For example, a joint RAN-DAS self-optimizing network (SON) entity can be communicatively coupled to the DAS head-end unit and one or more nodes of the RAN. The joint RAN-DAS-SON entity can receive operations and management (O&M) parameters specific to the RAN and O&M parameters specific to the DAS. Based on the DAS O&M parameters and RAN O&M parameters, the joint RAN-DAS-SON entity can determine target values for O&M parameters, which can indicate optimal optimization settings for the RAN and DAS. For example, the optimal optimization settings can include settings to tune the RAN and DAS for optimal coverage, capacity, or performance. In some aspects, optimization settings can include adjustments for the uplink / downlink gain of signals transmitted by the RAN or DAS to compensate for detected noise within the RAN and DAS. In other aspects, optimization settings can include re-allocating power levels of downlink signals transmitted by RAN nodes to account for changing traffic conditions. Other settings to tune the RAN and DAS for optimal coverage, capacity, or performance are also possible.

Jointly optimizing the RAN and a DAS through a joint RAN-DAS-SON entity can facilitate communication between RAN nodes and DAS head-end units and reduce delays caused by measuring and sending performance data between the DAS and the RAN. For example, without a joint RAN-DAS-SON entity, a base station in a RAN can compensate for uplink noise generated by the DAS by measuring for uplink noise offline first, and then separately adjusting uplink/downlink gain to compensate for the uplink noise through the O&M system of the base station. A joint RAN-DAS-SON entity can receive performance indicators indicating uplink noise level from the RAN and DAS and in response send instructions to the DAS head-end unit to modify the uplink gain or a DAS node to modify the downlink gain. Similarly, the joint RAN-DAS-SON entity can adjust for signal delay introduced by the DAS.

For example, the DAS can measure value of the delay introduced between the head end and the remote unit in both downlink and the uplink directions. This value can be reported to the joint RAN-DAS-SON entity which in turn can send an O&M command to the base station (i.e. the RAN Node). This command can be the Cell Radius O&M parameter used in the base station to configure the maximum expected delay in the cell served. The optimal value of the Cell Radius parameter can be calculated by the SON entity as follows: <MAT>.

Jointly optimizing the RAN and DAS through a joint RAN-DAS-SON entity can also make performance data of the RAN available to the DAS. The joint RAN-DAS-SON entity can detect changes to RAN performance data and make corresponding optimizations to DAS settings to tune the DAS to optimal performance characteristics.

These illustrative aspects and examples are given to introduce the reader to the general subject matter discussed here and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional features and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions may be used to describe the illustrative aspects but, like the illustrative aspects, should not be used to limit the present disclosure.

<FIG> is a logical block diagram depicting an example of a RAN-DAS architecture with a joint RAN-DAS-SON entity suitable for implementing the subject matter described herein. The RAN-DAS architecture can include a DAS with remote units 106a-d (each remote unit labeled "DAS RU" in <FIG>) communicatively coupled to a DAS head-end unit <NUM>. The head-end unit <NUM> can include an O&M application programming interface (API) <NUM>, which can be used to provide DAS O&M parameters to a joint RAN-DAS-SON entity <NUM>. Non-limiting examples of DAS O&M parameters can include downlink/uplink gain settings, frequency allocations, sector mapping settings, maximum input/output power levels, temperature controls, and measured interference levels.

The RAN-DAS architecture can also include a RAN with multiple operators. Each operator can have multiple RAN nodes associated with multiple technologies, sector identifiers, and carrier frequencies. As shown in <FIG>, RAN operator A can include RAN nodes 118a-d communicatively coupled to a core network 130a for operator A. RAN nodes 118a-d can each include an O&M API 122a-d for communicating RAN O&M parameters with the joint RAN-DAS-SON entity <NUM>. Non-limiting examples of RAN O&M parameters can include base station software stack control and monitoring parameters, radio front end processing parameters, media access control scheduler settings, radio resource management settings, and transport plane settings. RAN operator A can also include an element management system (EMS) / network management system (NMS) entity 126a communicatively coupled to the joint RAN-DAS-SON entity <NUM>. Similarly, RAN operator B can include RAN nodes 120a-d communicatively coupled to a core network 130b for operator B. RAN nodes 120a-d can also include O&M APIs 124a-d for communicating RAN O&M parameters to the joint RAN-DAS-SON entity <NUM>. RAN operator B can also include an EMS/NMS entity 126b communicatively coupled to the joint RAN-DAS-SON entity <NUM>. While <FIG> depicts joint RAN-DAS SON entity <NUM> separate from the RAN and DAS for illustrative purposes, in other aspects, the joint RAN-DAS SON entity <NUM> can be included in one of the RAN nodes 118a-d, 120a-d or in the head-end unit <NUM>.

The EMS/NMS entities 126a-b can include an EMS and an NMS specific to each respective operator. The EMS/NMS entities 126a-b can manage network elements of the respective operator networks. For example, EMS/NMS entities 126a-b can manage network administration tasks, identify network issues within the respective RAN, and manage the capacity of the RAN and identify areas of data congestion within each respective RAN. Each of the RAN nodes 118a-d and 120a-d can include a base station for providing downlink communications to the DAS head-end unit <NUM>. The base stations of each respective RAN node 118a-d and 120a-d can also receive uplink communications from the head-end unit <NUM> and provide the uplink communications to respective core networks 130a-b.

The joint RAN-DAS-SON entity <NUM> can receive RAN O&M parameters from RAN nodes 118a-d, 120a-d via a RAN O&M API <NUM>. The joint RAN-DAS-SON entity <NUM> can also receive DAS O&M parameters via a DAS O&M API <NUM>. The joint RAN-DAS-SON entity <NUM> can also receive communications from the EMS/NMS entities 126a-b via an EMS/NMS interface <NUM>. In some aspects, the joint RAN-DAS-SON entity <NUM> can receive EMS/NMS commands directly from RAN nodes 118a-d and 120a-d.

Based on the received RAN O&M parameters and DAS O&M parameters, the joint RAN-DAS-SON entity <NUM> can determine target O&M parameters for optimal configuration of elements of the RAN and DAS. Target O&M parameters can include various parameters for jointly optimizing the RAN and DAS. The target O&M parameters can include optimal configuration settings to optimize coverage characteristics, capacity characteristics, or performance characteristics of the RAN and DAS. For example, each of the RAN operators can have different key performance indicators that specify target performance guidelines such as network capacity requirements and minimum quality of service requirements. Each operator can adopt a specific policy on the visible/configurable parameters. In one aspect, the target O&M parameters determined by the joint RAN-DAS-SON entity <NUM> can be provided to the DAS head-end unit <NUM> and the individual RAN nodes 118a-d, 120a-d to modify RAN and DAS system parameters to ensure that the key performance indicators of the different operators are met. Further, the joint RAN-DAS-SON entity <NUM> can jointly manage the RAN and DAS to minimize the impact on one operator network (e.g., RAN nodes 120a-d) due to configuration changes in the other operator network (e. g, RAN nodes 118a-d). Further, the joint RAN-DAS-SON entity <NUM> can modify parameters specific to the DAS head-end unit <NUM> in order to optimize the DAS due to changes in the RAN configuration. Parameters specific to the head-end unit <NUM> that can be adjusted include the gain of signals transmitted by the head-end unit <NUM>.

In some aspects, target O&M parameters jointly configured by the joint RAN-DAS-SON entity <NUM> can include values to adjust the uplink gain of the DAS head-end unit <NUM>. For example, the uplink noise from a RAN node <NUM> can be used as a reference parameter to adjust the DAS uplink gain. The DAS head-end unit <NUM> can report the generated uplink noise power at the input port of the RAN node <NUM>, and the joint RAN-DAS-SON entity <NUM> can adjust the uplink gain of the DAS head-end unit <NUM> based on the uplink noise power reference of the RAN node <NUM>. If the head-end unit <NUM> uplink noise power exceeds the uplink noise power reference of the RAN node <NUM> byx dB due to the current DAS head-end unit <NUM> uplink gain, then the joint RAN-DAS-SON entity <NUM> can reduce the head-end unit <NUM> UL gain by x dB.

Another RAN O&M parameter that the joint RAN-DAS-SON entity <NUM> can use to optimize the DAS head-end unit <NUM> uplink gain is the P0nom target parameter of the RAN Node <NUM>. In the LTE wireless communication standard, the P0nom target parameter corresponds to the reference uplink nominal power. A target power level at the input of a DAS remote <NUM> can also be defined and available at the joint RAN-DAS-SON entity <NUM>. The joint RAN-DAS-SON entity <NUM> can set the uplink gain of the DAS head-end unit <NUM> so that: <MAT>.

In another aspect, the target uplink signal to interference-plus-noise ratio (SINR) of the RAN node <NUM> can be used by the joint RAN-DAS-SON entity <NUM> in order to optimize the number of DAS remote units <NUM> connected to the same RAN node <NUM> (i.e. the same sector). The number of remote units <NUM> connected to the same RAN node <NUM> is a target O&M parameter that can be referred to as the DAS simulcast factor. If the target uplink SINR of the RAN node <NUM> cannot be met due to excessive uplink noise from the DAS, the joint RAN-DAS-SON entity <NUM> can reduce the DAS simulcast factor and send a command to the DAS head-end unit <NUM> instructing the head-end unit <NUM> to reduce the DAS simulcast factor.

For example, if the target uplink SINR is equal to x dB, and the current uplink SINR is equal to x - <NUM> dB, then the joint RAN-DAS-SON entity <NUM> can instruct the DAS head-end unit <NUM> to reduce the simulcast factor by half (i.e. to reduce by half the number of remote units <NUM> connected to the same sector). Reducing the DAS simulcast factor by half can increase the uplink SINR of the RAN node <NUM> by 3dB and meet the target.

In additional aspects, the RAN O&M parameter indicating the number of active antennas of the RAN node <NUM> can be used by the joint RAN-DAS-SON entity <NUM> to optimize the number of active DAS remote units <NUM>. If the RAN node <NUM> reports that a secondary antenna port (e.g. in case of a 2x2 MIMO configuration) is not active, then the joint RAN-DAS-SON entity <NUM> can instruct the DAS head-end unit <NUM> to shut down the DAS remote units 106a-d communicatively linked to the secondary antenna port of the RAN node <NUM>. In addition to shutting down the DAS remote units 106a-d communicatively linked to the secondary antenna port, the DS head-end unit <NUM> can also shut down any other DAS module related to the secondary radio path.

In additional aspects, the target O&M parameter that the joint RAN-DAS-SON entity <NUM> can configure includes values to adjust the downlink gain of the head-end unit <NUM>. For example, the RAN node <NUM> can report the transmission output power of the RAN node <NUM> for a given carrier to the joint RAN-DAS-SON entity <NUM>. The joint RAN-DAS-SON entity <NUM> can also obtain information from the RAN node <NUM> regarding the desired target power for the given carrier as transmitted by the DAS remote unit <NUM>. The joint RAN-DAS-SON entity <NUM> can configure the DAS head-end unit <NUM> downlink gain in order to reach the target output power level at the remote unit <NUM> as follows: <MAT>.

The joint RAN-DAS SON entity <NUM> can also configure the DAS head-end unit <NUM> downlink gain based on the output power and target output power of a pilot signal. For example, the RAN node <NUM> can also report to the joint RAN-DAS-SON entity <NUM> the output power of the pilot signal from the RAN node <NUM>. The DAS head-end unit <NUM> can report the target output pilot power at the DAS remote unit <NUM>. The joint RAN-DAS SON entity <NUM> can configure the DAS head-end unit <NUM> downlink gain according to the same formula above. In some aspects, the optimal setting for the DAS head-end unit <NUM> downlink gain can also be a negative value, in which case the joint RAN-DAS SON entity <NUM> can attenuate the downlink gain of the head-end unit <NUM>.

In other aspects, the Low Noise Amplifier (LNA) gain in the uplink path of the RAN node <NUM> can be reported to the joint RAN-DAS SON entity <NUM>. In order to optimize the uplink path performance of the RAN and DAS combined system, the joint RAN-DAS SON entity <NUM> can switch off the LNA of the RAN node <NUM> and set the uplink gain of the DAS head-end unit <NUM> equal to the gain of the LNA of the RAN node <NUM>. In some aspects, a Tower Mounted Amplifier (TMA) gain setting may be available at the RAN node <NUM>. The joint RAN-DAS SON entity <NUM> can set the uplink gain of the TMA of the RAN node <NUM> to a value equal to: <MAT>.

In additional aspects, the RAN node <NUM> can report to the joint RAN-DAS SON entity <NUM> information related to the frequency, technology, channel bandwidth, Mobile Country Code, Mobile Network Code of the radiated cell signals, including other information the RAN node <NUM> may broadcast to the network. The joint RAN-DAS SON entity <NUM> can relay this information to the DAS head-end unit <NUM>, and to the DAS controller within the head-end unit <NUM> more specifically.

The RAN node <NUM> can also provide RAN O&M parameters including information indicating the current Transmission Mode (TM) to the joint RAN-DAS SON entity <NUM>. For example, the TM can correspond to various antenna transmission configurations including SISO, MIMO TX Diversity, or MIMO Spatial Multiplexing (open loop or closed loop). If the RAN node <NUM> operates in a closed loop TM, then the RAN node <NUM> also may also provide the Pre-coding Matrix Indicator (PMI) in operation, which depends on the type of phase shift (e.g., +- <NUM>, +-<NUM> degrees, or others) the RAN node <NUM> applies to the transmitted signals. The joint RAN-DAS SON entity <NUM> can report the parameters including the TM and the PMI to the DAS head-end unit <NUM>, and to the DAS controller more specifically. The DAS head-end unit <NUM> can apply another phase-shift to the received signals according to the phase shift applied by the RAN node <NUM>. By coherent combining o the phase shifted signals at the DAS head-end unit <NUM>, the desired signal strength can be maximized and the undesired signals can be canceled.

In additional aspects, the traffic load on a given cell can be also reported by the RAN node <NUM> to the joint RAN-DAS SON entity <NUM>. In case the reported traffic load is higher than a given threshold for a given DAS simulcast configuration (i.e. the number of DAS remote units <NUM> radiating the same cell signal), then the joint RAN-DAS SON entity <NUM> can instruct the DAS head-end unit <NUM> to reduce the DAS simulcast factor (e.g., assign fewer remote units to the same cell signal). The DAS head-end unit <NUM> can use a signal switching function to route the cell signal to different remote units <NUM>.

In another aspect, instead of determining the target O&M parameters, the joint RAN-DAS-SON entity <NUM> can operate in a "slave" mode by forwarding RAN O&M parameters and DAS O&M parameters to the EMS/NMS entities 126a-b. The EMS/NMS entities a-b can determine optimal configuration settings for the RAN and DAS and provide instructions on the configuration settings to the joint RAN-DAS-SON entity <NUM>. Using the instructions from the EMS/NMS entities 126a-b, the joint RAN-DAS-SON entity <NUM> can optimize the RAN and DAS to optimize coverage characteristics, capacity characteristics, or performance characteristics.

<FIG> is a block diagram depicting an example of a joint RAN-DAS-SON entity <NUM> according to one aspect. The joint RAN-DAS-SON entity <NUM> can include a system bus <NUM> that can communicatively couple an analysis module <NUM> with the RAN O&M API <NUM>, and a DAS O&M API <NUM>.

The analysis module <NUM> can include a processing device <NUM> and a memory device <NUM>. The processing device <NUM> can include any device suitable for executing program instructions to control operation of the joint RAN-DAS-SON entity <NUM>. Examples of processing device <NUM> include a microprocessor, an application-specific integrated circuit ("ASIC"), a field-programmable gate array ("FPGA"), or other suitable processor. The processing device <NUM> may include one processor or any number of processors. The memory device <NUM> can include any non-transitory media for storing program code defining the operations of the joint RAN-DAS-SON entity <NUM>. Non-limiting examples of memory device <NUM> can include read-only memory (ROM), random-access memory (RAM), optical storage, magnetic storage, flash memory, or any other medium from which the processing device <NUM> can read program code.

The memory device <NUM> can include program code defining instructions that, when executed by the processing device <NUM>, cause the joint RAN-DAS-SON entity <NUM> to switch between a "master" mode, a "slave" mode, and a "hybrid" mode. While operating in a "master" mode, the joint RAN-DAS-SON entity <NUM> can determine target O&M parameters based on received DAS O&M parameters and RAN O&M parameters. The target O&M parameters can be provided as instructions to the appropriate RAN nodes 118a-d, 120a-d or DAS head-end unit <NUM>. While operating in a "slave" mode, the joint RAN-DAS-SON entity <NUM> can forward DAS O&M parameters and RAN O&M parameters to EMS/NMS entities 126a-b. The joint RAN-DAS-SON entity <NUM> can also forward instructions on optimal configuration received from the EMS/NMS entities 126a-b to RAN nodes 118a-d, 120a-d, and to DAS head-end unit <NUM> via the RAN O&M API <NUM> and the DAS O&M API <NUM>, respectively. In a "hybrid" mode, a portion of the O&M target parameters can be determined by the joint RAN-DAS-SON entity <NUM> and a second portion of the O&M target parameters can be determined by the EMS/NMS entities 126a-b and forwarded to the appropriate RAN nodes 118a-d, 120a-d or DAS head-end unit <NUM>. In some aspects, each operator of the RAN can specify different optimization algorithms for the joint RAN-DAS-SON entity <NUM>. In this context, each operator can select which target O&M parameters should be determined at the joint RAN-DAS-SON entity <NUM> and which target O&M parameters can be centrally managed at the EMS/NMS entities 126a-b.

<FIG> is a flowchart depicting a process <NUM> for jointly optimizing a RAN and DAS architecture based on collected O&M parameters. In block <NUM>, the joint RAN-DAS-SON entity <NUM> can collect a first set of O&M parameters. For example, the joint RAN-DAS-SON entity <NUM> can collect RAN O&M parameters from each of the RAN nodes 118a-d, 120a-d via the RAN O&M API <NUM> included in the joint RAN-DAS-SON entity <NUM>. In some aspects, the joint RAN-DAS-SON entity <NUM> can request each RAN node 118a-d, 120a-d to a set of RAN O&M parameters at a particular point in time. In other aspects, each base station in the RAN nodes 118a-d, 120a-d can periodically transmit measured RAN O&M parameters to the joint RAN-DAS-SON entity <NUM>. As mentioned above, RAN O&M parameters from a particular RAN node 118a can include various control parameters specific to the operator for the RAN node 118a.

In block <NUM>, the joint RAN-DAS-SON entity <NUM> can collect a second set of O&M parameters. For example, the joint RAN-DAS-SON entity <NUM> can collect DAS O&M parameters from the DAS head-end unit <NUM> similar to the steps described with respect to block <NUM>. As mentioned above, DAS O&M parameters can include control and signaling parameters specific to the DAS.

The joint RAN-DAS-SON entity <NUM> can determine target O&M parameters based on the first set of O&M parameters and the second set of O&M parameters, as shown in block <NUM>. Target O&M parameters can include optimal configuration settings for jointly configuring the RAN and the DAS. For example, the first set of O&M parameters (e.g., RAN O&M parameters) may include key performance indicators indicating network performance guidelines and minimum quality of service requirements. The joint RAN-DAS-SON entity <NUM> can determine the target O&M parameters that would meet the performance guidelines specified by the key performance indicators. As another example, the first set of O&M parameters can indicate measured uplink noise detected by base stations at RAN nodes 118a-d, 120a-d. In response, the joint RAN-DAS-SON entity <NUM>, via the analysis module <NUM>, can determine target O&M parameters to compensate for the uplink noise. Target O&M parameters to compensate for uplink noise can include instructions for increased gain at the head-end unit <NUM>. Similarly, the joint RAN-DAS-SON entity <NUM> can determine target O&M parameters and provide instructions to the base stations at RAN nodes 118a-d, 120a-d to adjust downlink gain to compensate for downlink noise measured at the head-end unit <NUM>.

In another aspect, the joint RAN-DAS-SON entity <NUM> can be configured to operate in a "slave" mode and forward the first set of O&M parameters and second set of O&M parameters to the EMS/NMS entities 126a-b. The EMS/NMS entities 126a-b can determine the target O&M parameters and generate instructions regarding optimizing the RAN and DAS to meet the target O&M parameters.

Based on the first set of O&M parameters, second set of O&M parameters, and the target O&M parameters, the joint RAN-DAS-SON entity <NUM> can jointly optimize the RAN and the DAS, as indicated in block <NUM>. For example, while the joint RAN-DAS-SON entity <NUM> operates in a "master" mode, the analysis module <NUM> can determine instructions for optimizing characteristics of the RAN and DAS to obtain the target O&M parameters. The joint RAN-DAS-SON entity <NUM> can provide the instructions regarding the target O&M parameters to the RAN nodes 118a-d, 120a-d to optimize aspects of the RAN. The joint RAN-DAS-SON entity <NUM> can also provide the instructions regarding the target configuration settings to the DAS head-end unit <NUM> to optimize aspects of the DAS. As discussed above, jointly optimizing the RAN and the DAS can improve the capacity characteristics, coverage characteristics, or the performance characteristics of the RAN and DAS. When the joint RAN-DAS-SON entity <NUM> operates in a "slave" mode, the joint RAN-DAS-SON entity <NUM> can jointly optimize the RAN and DAS by forwarding instructions from the EMS/NMS entities 126a-b to the RAN nodes 118a-d, 120a-d and the head-end unit <NUM>.

In some aspects, the joint RAN-DAS-SON entity <NUM> can optimize the RAN and DAS by re-allocating power levels across downlink carriers based on low traffic conditions detected on one or more downlink carriers. For example, RAN nodes 118a-d, 120a-d can each transmit a different downlink carrier signal at varying power levels defined during initialization of the DAS. The power levels of the individual downlink carrier signals can be independently calculated to meet specific key performance indicators for remote units 106a-d. For example, key performance indicators for remote units 106a-d may specify that the downlink carrier signals are transmitted at a minimum pilot power level. Each remote unit 106a-d can transmit the multiple carrier signals to user devices.

During operation of the RAN and DAS, however, low traffic conditions may exist for one or more of the downlink carrier signals, such that some of the allocated power is unused. Low traffic conditions can thus result in inefficient power distribution due to unused bandwidth. When a given downlink carrier signal is associated with a low traffic load, the joint RAN-DAS-SON entity <NUM> can redistribute the power allocation across the downlink carriers to optimize the RAN and DAS.

For example, <FIG> are tables depicting an example of power allocation and re-allocation across four downlink carrier signals from RAN nodes 118a-d and remote unit <NUM>. <FIG> depicts the power level per downlink carrier signal provided by RAN nodes 118a-d, each RAN node 118a-d respectively transmitting one carrier signal 402a-d. During initialization of the RAN and DAS, initial power allocation for the signals transmitted by RAN nodes 118a-d can be evenly divided as shown in row <NUM>, each RAN node 118a-d transmitting <NUM> decibel-milliwatts (dBm) when transmitting for full traffic load. During operation of the RAN and DAS, one carrier signal 402a may exhibit no traffic load, in which case RAN node 118a can transmit carrier signal 402a at a reduced power level of <NUM> dBm.

<FIG> depicts a table showing example power levels of the downlink carrier signals 402a-d transmitted by remote unit <NUM>. Row <NUM> depicts power level per carrier signal as transmitted by remote unit <NUM> upon initialization of the RAN and DAS. As in <FIG>, initial power allocation for signals transmitted by remote unit <NUM> can be evenly divided, remote unit <NUM> transmitting all four carrier signals 402a-d at <NUM> dBm. Row <NUM> also indicates that the remote unit <NUM> applies a downlink gain of -<NUM> dB to each carrier signal 402a-d. Row <NUM> depicts the power level per carrier signal as transmitted by remote unit <NUM> when there is no traffic load on carrier signal 402a. Carrier signal 402a can be transmitted at a power level of <NUM> dBm, while carrier signals 402b-d may be transmitted at power levels of <NUM> dBm. Without any optimization of the RAN and DAS, the remote unit <NUM> can continue to apply a downlink gain of -<NUM> dB to each carrier signal 402a-d. Row <NUM> depicts the power level per carrier signal as transmitted by remote unit <NUM> after the joint RAN-DAS-SON entity <NUM> optimizes the RAN and DAS by boosting the power levels of downlink carrier signals with a minimum traffic load. Due to the low traffic conditions of carrier signal 402a, the excess downlink power can be re-distributed and applied to carrier signals 402b-d. The joint RAN-DAS-SON entity <NUM> can calculate a <NUM> dB gain boost for each of the carrier signals 402b-d. Upon applying the boosting factor, while carrier signal 402a (with no traffic load) is transmitted at a power level of <NUM> dBm (-<NUM> dB gain), power levels of carrier signals 402b-d can each increase to <NUM> dBm (-<NUM> dB gain). The composite power of the remote unit <NUM> remains constant.

In some aspects, the joint RAN-DAS-SON entity <NUM> can receive the traffic load information on each downlink carrier signal and optimize the transmission power levels of remote units based on the traffic load information. For example, the joint RAN-DAS-SON entity <NUM> can receive traffic load information as part of RAN O&M parameters received from RAN nodes 118a-d, 120a-d. One non-limiting example of traffic load information is information indicating the number of user devices connected to and in communication with RAN nodes 118a-d, 120a-d. Another example of traffic load information is information indicating the amount of bandwidth of the total signal bandwidth used by user devices connected to and in communication with RAN nodes 118a-d, 120a-d. The DAS head-end unit <NUM> can also receive traffic load information from the RAN nodes 118a-d, 120a-d and provide the traffic load information to the joint RAN-DAS-SON entity <NUM> as part of DAS O&M parameters. The DAS head-end unit <NUM> can also measure the traffic load information by demodulating each received downlink signal from RAN nodes 118a-d, 120a-d and provide the traffic load information to the joint RAN-DAS-SON entity <NUM>.

The traffic load information can indicate to the joint RAN-DAS-SON entity <NUM> the traffic load on each downlink carrier from RAN nodes 118a-d, 120a-d. Based on the traffic load information, the joint RAN-DAS-SON entity <NUM> can determine target operations and management parameters for optimizing the RAN and DAS by re-allocating excess signal power to other downlink carriers. For example, for any downlink carrier signal that has a traffic load less than a predefined threshold, the joint RAN-DAS-SON entity <NUM> can calculate the power headroom available for the carrier signal (e.g., the amount of allocated power that is unused due to the low load traffic conditions). The power headroom for a given carrier signal can be the difference between the maximum possible power of a carrier signal and the actual power transmitted by a remote unit <NUM> to provide wireless communication to connected user devices.

The joint RAN-DAS-SON entity <NUM> can allocate the measured power headroom available for the low threshold carrier signal to the other carrier signals transmitted by the remote unit <NUM>. For example, based on the calculated power headroom, the joint RAN-DAS-SON entity <NUM> can determine a boosting factor to apply to the carrier signals associated with traffic loads higher than the predefined threshold transmitted by the remote unit <NUM>. The boosting factor can include the amount of downlink gain to apply to each of the carrier signals with higher traffic load. In some aspects, target operations and management parameters determined by the joint RAN-DAS-SON entity <NUM> can include the boosting factor. The joint RAN-DAS-SON entity <NUM> can optimize the RAN and DAS by providing the boosting factor to the head-end unit <NUM>. The head-end unit <NUM> can provide the boosting factor to the appropriate remote unit <NUM>, which can amplify the downlink gain associated with the carrier signals with higher traffic load according to the amount of the boosting factor. In other aspects, the joint RAN-DAS-SON entity <NUM> can optimize the RAN and DAS by directly instructing the appropriate remote unit <NUM> to amplify downlink gain associated with the carrier signals with higher traffic load according to the amount of the boosting factor.

Claim 1:
A telecommunications system including a radio access network, RAN, and a distributed antenna system, wherein the distributed antenna system includes a head-end unit (<NUM>) and one or more remote units (<NUM>), wherein the head-end unit (<NUM>) of the distributed antenna system is communicatively coupled between one or more RAN nodes (<NUM>, <NUM>) and the one or more remote units (<NUM>), the telecommunications system comprising:
a joint radio access network-distributed antenna system-self optimizing network, RAN-DAS-SON, entity (<NUM>), wherein the joint RAN-DAS-SON entity (<NUM>) is configured to jointly optimize the radio access network and the distributed antenna system;
a node (<NUM>, <NUM>, <NUM>), wherein the node (<NUM>, <NUM>, <NUM>) is the head-end unit (<NUM>) of the distributed antenna system or a RAN node (<NUM>, <NUM>), the node (<NUM>, <NUM>, <NUM>) comprising an interface (<NUM>, <NUM>) configured to communicate parameters with the joint RAN-DAS-SON entity (<NUM>);
wherein the node (<NUM>, <NUM>, <NUM>) is configured to:
transmit a first set of parameters to the joint RAN-DAS-SON entity (<NUM>);
receive instructions regarding target parameters for jointly optimizing the radio access network and the distributed antenna system from the joint RAN-DAS-SON entity (<NUM>);
when the node (<NUM>, <NUM>, <NUM>) is the head-end unit (<NUM>), adjust one or more configuration settings of the node (<NUM>) and/or one or more configuration settings of one or more remote units (<NUM>) communicatively coupled to the node (<NUM>) based on the instructions regarding target parameters for jointly optimizing the radio access network and the distributed antenna system from the joint RAN-DAS-SON entity (<NUM>); and
when the node (<NUM>, <NUM>, <NUM>) is the RAN node (<NUM>, <NUM>), adjust one or more configuration settings of the node (<NUM>, <NUM>) based on the instructions regarding target parameters for jointly optimizing the radio access network and the distributed antenna system from the joint RAN-DAS-SON entity (<NUM>).