The present invention relates generally to the field of wireless communications. More particularly, the present invention relates to dynamically modifying the configuration space of self-configuring wireless communication systems.
This section is intended to provide a background or context to the disclosed embodiments that are recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
In cellular networks, radio nodes, also sometimes referred to as base stations, access points, Node Bs, eNode Bs, cells and the like, are normally installed and commissioned after a careful upfront planning and survey process, which is followed by extensive post installation optimization efforts to maximize the network performance. Such optimization efforts usually involve a considerable amount of manual intervention that could include “drive testing” using specialized measurement devices to collect data on network performance at a variety of geographical locations. This data is then post-processed and analyzed to effect optimization steps including power adjustments, antenna tilt adjustments and the like. As a result of such elaborate network planning and optimization operations, the exact number of operating radio nodes, the coverage area of each radio node, the transmit power levels, and other parameters associated with the network is determined and fine-tuned.
In a small-cell (e.g., local area) networks that are installed and operated relatively inexpensively, such expensive planning and post-installation fine tuning of the network is not economically feasible. For example, such installation procedures may be prohibitive in enterprise networks, as well as applications that relate to high-density capacity enhancements of a downtown city square and ad-hoc deployment of a cellular network such as in military applications. Nevertheless, proper configuration and optimization of such networks is important for enabling efficient utilization of network resources. In order to properly allocate the necessary resources for operation of the network, configuration settings must be selected from within a set of configuration parameters. The size of the configuration space is typically set arbitrarily by a human operator without having a detailed knowledge of the radio frequency (RF) characteristics of the deployment area, the exact number of radio nodes and other network information. Therefore, the allocated configuration space may be too large or too small, which can lead to inefficient use of network resources, interference in uplink and downlink communications and problems associated with handoff operations.
The disclosed embodiments relate to methods, devices, and computer program products that enable optimization of the configuration space in a network.
According to one aspect of the invention, there is provided a method that includes provisioning a self-configuring communication network in accordance with a configuration space, producing feedback information indicative of the sufficiency of the configuration space, determining whether the configuration space is sufficient based on the feedback; and if the configuration space is determined to be insufficient, updating the configuration space based on the feedback.
According to another aspect of the invention, there is provided a device that includes a processor, and a memory comprising processor executable code, the processor executable code, when executed by the processor, configures the apparatus to:
provision a self-configuring communication network in accordance with a configuration space,produce feedback information indicative of the sufficiency of the configuration space, determine whether the configuration space is sufficient based on the feedback, and if the configuration space is determined to be insufficient, updating the configuration space based on the feedback.
According to yet another aspect of the invention, there is provided a computer program product, embodied on a computer readable medium, comprising:
program code for provisioning a self-configuring communication network in accordance with a configuration space,program code for producing feedback information indicative of the sufficiency of the configuration space, program code for determining whether the configuration space is sufficient based on the feedback, and if the configuration space is determined to be insufficient, program code for updating the configuration space based on the feedback.
These and other advantages and features of various embodiments of the present invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Embodiments of the invention are described by referring to the attached drawings, in which:
In the following description, for purposes of explanation and not limitation, details and descriptions are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these details and descriptions.
Additionally, in the subject description, the word “exemplary” is used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word exemplary is intended to present concepts in a concrete manner. Further, some of the disclosed embodiments are described in the context of an enterprise network. However, it should be understood that the disclosed principles are equally applicable to other types of networks.
Some smaller scale cellular networks, including femtocells and enterprises networks, utilize self-configuration and self-organizing techniques that are based on on-going measurements of the RF environment to obtain the network topology. For example, see U.S. patent application Ser. No. 12/957,181, entitled “METHOD, SYSTEM AND DEVICE FOR CONFIGURING TOPOLOGY OF A WIRELESS NETWORK,” filed Nov. 30, 2010, and assigned to the present assignee. This application is hereby incorporated by reference in its entirety. Additionally, large-scale networks may also utilize self-configuration and self-organizing techniques that are based on on-going measurements of the RF environment to obtain the network topology, in accordance with the embodiments of the invention described herein.
Self-configuring networks must select their configuration settings from within a configuration space (i.e., a set of self-configurable parameters that are allowed to take on a limited set of values). For example, the network may be allowed to self-configure the transmit power of each radio node within the range 0 dBm and 10 dBm. As another example specific to Universal Mobile Telecommunication System (UMTS), the network may be allowed to self-configure the primary scrambling code (PSC) associated with each radio node using a set of allowable PSC's. The configuration space is often set by an operator. For example, a network operator may set the configuration space to restrict radio node transmit powers within the range 0 dBm and 10 dBm, and PSC's values within the range 200 to 209. As another example, a network operator may set the configuration space to restrict PSC's values to a list of ranges and/or singletons. In an example specific to Long Term Evolution (LTE), various other parameters such as the physical cell ID (PCI), neighbor relations, maximum down link cell or eNodeB power, the reference or pilot signal power, or down link channel bandwidth may be self-configured.
When setting up the configuration space for a self-configuring network, the operator generally does not want to maximize the size of the configuration space. For example, allowing a large maximum transmit power level can potentially allow the self-configuring network to cause excessive interference in the local macro network. In another example, allowing a large set of allowable PSCs can lead to excessive interference and/or a potential to cause ambiguity that leads to handoff problems. Such ambiguity and/or interference can be caused due to the use of identical PSCs by independent self-configuring networks that are within communication range of the self-configuring network, the macro network, or a set of autonomous home Node-B's. The potential for ambiguity associated with assigning a large number of PSCs can be further illustrated in an example scenario where a user within a macro cell reports a particular PSC as being “strong” or desirable for handoff purposes. If the PSC is reused within multiple, independent self-configuring networks deployed around that macro cell, there is an ambiguity as to which cell the reported PSC refers to. On the other hand, allocating a small range of assignable PSCs can also lead to excessive interference due to PSC reuse within the self-configuring network, as well as potential delays in establishing communication sessions within the self-configuring network.
When deploying a self-configuring network, the operator may not be fully aware of the detailed topology and RF propagation environment of the network. Therefore, the operator is often unable to set up a configuration space of proper size, which can lead to unpredictable network performance problems. For example, to reduce downlink interference and to avoid handoff problems, every radio node within a local area should have a unique PSC. At the time of network deployment, the operator does not know the RF characteristics of the deployment and is thus unaware of the exact number of radio nodes within the local area. The operator may also not be aware of the particular scrambling codes used by other networks, such as home NodeB's or other femtocells that are operating in the vicinity of the self-configuring network. Therefore the operator is not be able to predict the appropriate range of PSC's that must be included in the configuration space.
The disclosed embodiments enable automatic and dynamic allocation of the configuration space for self-configuring networks. The disclosed embodiments rely on the feedback that is received from one or more entities within the self-configuring network to discern whether or not the configuration space, or portions thereof, is suitable for efficient operation of the network. In response, the configuration space is automatically adjusted to accommodate the needs of the self-configuring network. The configuration space can include a variety of parameters, and the associated ranges, that facilitate proper operation of the network. By the way of example, and not by limitation, the configuration space parameters include a range of transmit power levels associated with radio nodes, a minimum assignable transmit power level for each radio node, a maximum assignable transmit power level for each radio node, cell, and/or NodeB or eNodeB (for TR-196 self-configuration object, there can be assigned a minimum value and a maximum value for maximum assignable transmit power level), a set of assignable primary scrambling codes or physical cell IDs (PCI), a set of channels (e.g., Universal Terrestrial Radio Access Absolute Radio Frequency Channel Numbers (UARFCN)) or E-UTRA Absolute Radio Frequency Channel Numbers (EARFCN) available for use by the network, one or more cell identifiers (CID) to identify the cells within a radio network subsystem (RNS), a radio network controller identifier (RNCID), which may be used in conjunction with the CIDs, a maximum uplink transmit power value to be used by the user equipment in the network, minimum and maximum downlink power values associated with a primary common pilot channel (PCPICH) in UMTS systems or reference signal in LTE, a femto access point (FAP) Coverage Target value, which defines the target value for the range of a FAP's downlink coverage in terms of RF propagation loss, the download channel bandwidth in LTE, and the like. It should be also noted that one or more of the configuration space parameters may be presented as a range of values, rather than a single value. For example, the maximum uplink transmit power for each user equipment may be specified as a range of maximum transmit power values (e.g., a lower and an upper maximum transmit power value), in which the lower bound on the maximum transmit power may be used to ensure a minimum coverage area for a cell. As another example, the downlink transmit power for each user equipment may be specified as a range of downlink transmit powers.
The exemplary block diagram that is shown in
It should be noted that while the exemplary radio networks that are depicted in
In step 504, the self-configuring network is provisioned within the configuration space that was set up in step 502. For example, by reference to
As noted earlier, it is possible that the initial configuration space is not suitable for the self-configuring network. For example, the self-configuring network 300 or EMS 410 may determine that the set of assignable PSCs or PCIs is too small because the same PSC or PCI has to be assigned to two radio nodes that are first- or second-tier neighbors of each other. The suitability determination may be based on measurements and information of external network cells as well as internal network cells and user equipment. For example, the determination that the assignable PSC or PCI values is too small may in part include the detection of overlapping PSCs or PCIs used by neighboring external cells. As a result, a radio node can have two neighboring radio nodes with the same PSC or PCI, which can cause both interference and handoff problems.
It can be learned and reported when PSCs or PCIs are reused too closely through UE feedback. For example, in a UMTS system, the UE reports a PSC. When an attempt to add a link is made, it can be determined that it was added on an incorrect self-configuring radio node/NodeB based on timing or radio link sync failure. In another scenario, a UE reports a PSC and a Cell ID. A problem can be detected if the E-RAN knows that there is another Cell with the same PSC but a different Cell ID in the same area, perhaps through a previous scan or through a UE reporting the same PSC with a different Cell ID in the past. In an LTE system, the UE reports a PCI. When an attempt to add a link is made, it can be determined that it was added on an incorrect LTE cell/eNodeB based on timing or radio link sync failure. In another scenario, when the UE reports a PCI, the E-RAN asks the UE to decode and report the E-UTRAN Cell Global Identifier (ECGI). A problem can be detected if the E-RAN knows of another Cell with the same PCI but a different ECGI in the area, perhaps through a previous scan or through a UE reporting the same PCI with a different ECGI in the past.
The concept of multi-tier neighbors can be explained by reference to the simplified depiction of
By way of example, and not limitation, various other things can be learned and reported that might be relevant for self-configuration of the network. For example, it can be learned and reported when the self-configuring radio nodes (NodeBs or eNodeBs) are too far away from each other. This could be based on when detected signal strengths are determined to be too weak during scan operations or when self-configured neighbor lists or neighbor relations are too spare. Similarly, it can be learned and reported when self-configuring radio nodes (NodeBs or eNodeBs) are too close to each other. This could be based on when detected signal strengths are too strong during scan operations. It is also possible to determine when the load across networks cannot be balanced. This could indicate that an additional radio node or physical change of radio node locations might be helpful.
Referring back to
Table 1 provides examples of the information that may be produced in step 508. It should be noted that the exemplary listings of Table 1 are only produced to facilitate the understanding of the underlying concepts, and additional or fewer information may be produced in step 508 of
After the generation of the information in step 508 of
Once the produced information is communicated to the operator 308 or Configuration Space Selection Module 412, the configuration space is updated in step 512. The updated configuration space can then be communicated to the network (not shown), where it is used to modify the existing system resource allocations to accommodate the network requirements. In one example, the updated configuration space can be communicated to a central controller associated with the self-configuring network (e.g., to the services node 304, 404 depicted in
After receiving and/or accessing the updated configuration space, the process returns to step 504, where the network is reconfigured based on the updated configuration space. The process that is describes in steps 504 to 510 can continue until an optimized configuration space is produced. In some embodiments, the reconfiguration of a self-configuring network may further trigger a self-configuration process in another self-configuring network. For example, the feedback may indicate that a first self-configuring network needs a larger set of PSCs. After the first self-configuring network iterates with the new configuration space, a neighboring self-configuring network may need to scan its environment to discover the new PSC assignments for its neighbors. In one example, the operator may trigger the self-configuration of the neighboring network to occur.
In the context of the block diagram of
In some embodiments, the power level assignment for each radio node (e.g., the minimum and maximum transmit power level) may be modified based on long-term assessments of the RF environment by the radio nodes of the self-configuring network. For example, each radio node may conduct periodic RF measurements that can be analyzed to determine the presence of “coverage holes” and/or excessive interference from neighboring radio nodes. In this context, rather than immediately reporting an adequacy or inadequacy of the transmit powers to the operator, the process that is depicted in
In other example scenarios, an indication regarding adequacy/inadequacy of a first portion of the configuration space is produced at a different time than an indication regarding adequacy/inadequacy of a second portion of the configuration space. For example, an indication regarding the inadequacy of the number of PSCs may be sent immediately after configuration of the network with an initial (or updated) set of PSCs, while an indication as to the inadequacy of maximum transmit power levels may be triggered after several iterations of power measurement/adjustment by the self-configuring network. Using this technique, unnecessary updates to the configuration space due to transient network conditions are also avoided.
Configuration space updates can also be triggered by other events and/or observations of the self-configuring network. This can be performed by way of a two-step process. In a first step, the observations may first trigger a reconfiguration of the self-configuring network. This could be autonomous (self-configuring network just goes ahead and reconfigures itself). This could be an indication to the operator that it should reconfigure itself, and the operator then indicates that it should reconfigure itself. In a second step, when the self-configuring network attempts to reconfigure itself, in the process it learns that its current configuration space is insufficient. From that, it will follow the steps shown in
As also indicted by the last entry of Table 1, the self-configuring network or Self-Configuration Feedback Processing Module can determine that the configuration space is larger than what is needed for efficient operation of the network and, accordingly, notify the operator. For example, the self-configuring network or Self-Configuration Feedback Processing Module may determine that an original set of 30 PSCs is larger than necessary to meet a target goal, and the network only needs 20 PSCs achieve a suitable configuration.
While some of the exemplary embodiments have been described in the context of a self-configuring and self-optimizing wireless network that utilize one or more central controllers, it is understood that the disclosed embodiments are equally applicable to networks without a central controller (e.g., an autonomous collection of femtocells). In a de-centralized network, direct radio node-to-radio node communications (over the air or through a wired communication link) may be carried out to assess the suitability of the configuration space, and to provide the pertinent information for mitigating the shortcomings of the configuration space to an operator. In such de-centralized architectures, the radio nodes have the capability to conduct various scans and measurements, analyze the results of the scans and measurements, and communicate the result to one or more other radio nodes and/or to the operator. Similarly, the disclosed embodiments can be applied to hybrid systems that utilize both a central controller and peer-to-peer radio node communications.
It is understood that the various embodiments of the present invention may be implemented individually, or collectively, in devices comprised of various hardware and/or software modules and components. These devices, for example, may comprise a processor, a memory unit, an interface that are communicatively connected to each other, and may range from desktop and/or laptop computers, to consumer electronic devices such as media players, mobile devices and the like. For example,
The various components or sub-components within each module of the disclosed embodiments may be implemented in software, hardware, firmware. The connectivity between the modules and/or components within the modules may be provided using any one of the connectivity methods and media that is known in the art, including, but not limited to, communications over the Internet, wired, or wireless networks using the appropriate protocols.
Various embodiments described herein are described in the general context of methods or processes, such as the processes described in
The foregoing description of embodiments has been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit embodiments of the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments. For example, the disclosed embodiments are equally applicable to networks that utilize different communication technologies, including but not limited to UMTS (including R99 and all high-speed packet access (HSPA) variants), as well as LTE, WiMAX, GSM and the like. The embodiments discussed herein were chosen and described in order to explain the principles and the nature of various embodiments and its practical application to enable one skilled in the art to utilize the present invention in various embodiments and with various modifications as are suited to the particular use contemplated. The features of the embodiments described herein may be combined in all possible combinations of methods, apparatus, modules, systems, and computer program products.
This application is a non-provisional patent application based on U.S. Provisional Patent Application No.: 61/472,130, filed Apr. 5, 2011, which is incorporated herein in its entirety.
Number | Date | Country | |
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61472130 | Apr 2011 | US |