Method and system for allocating physical layer sub-cell identities in wireless networks

Abstract

Embodiments of the present invention include methods, systems, and software for physical layer subcell identity allocation to select a subcell identity vector for a network device in a wireless network. In one embodiment, the method includes selecting a plurality of subcell identity vector candidates for the network device from a set of possible subcell identity vector candidates, wherein the selecting removes one or more possible subcell identity vector candidates that contain the same subcell identity for two or more adjacent sectors of the network device. The method also includes determining a plurality of conflict measurements for each of the plurality of subcell identity vector candidates. The method then proceeds by deriving a single value from the plurality of conflict measurements for each of the plurality of subcell identity vector candidates, and selecting a subcell identity vector for the network device from the plurality of subcell identity vector candidates based on the single value.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of networking; and more particularly, to allocating physical layer sub-cell identities in a wireless network. Background Art

[0002] Wireless network standards such as Long Term Evolution (LTE) and fifth-generation cellular network technology, New Radio (5G NR), define two downlink synchronization signals: the Primary Synchronization Signal (PSS) and the Secondary Synchronization Signal (SSS). The PSS and SSS are used to achieve subframe, slot, and symbol synchronization in the time domain. For cell search, detecting the PSS and SSS is a prerequisite for measuring the cell-specific reference signal (CRS) and decoding the master information block (MIB) on the physical broadcast channel (PBCH). Cell synchronization is the first step during the cell search process in some wireless networks (e.g., initial terminal device camping, terminal device handover between base stations).

[0003] The physical cell identifier (PCI) is an identifier of a cell in the physical layer of a wireless network, which can be used to distinguish different transmitters. The PCI can be represented as a combination of a physical layer cell identifier group (referred to as a PCI group, typically represented by physicalLayerCellIdGroup) and a physical layer sub-cell identifier (interchangeably referred to as PCI-ID, PCI-Sub-cell-ID, Sub-cell-ID, or Subcell ID, and typically represented by physicalLayerSubCellId). The PSS can be used to identify the center of the channel bandwidth in the frequency domain and to derive a pointer to one of the three physical layer sub-cell identifiers, while the SSS can be used to identify the PCI group number.

[0004] PCI planning (also known as PCI allocation, selection, or management) is the process of assigning PCIs to cells and cell sectors. Existing methods focus on identifying appropriate PCIs or PCI groups to maximize PCI reuse distance. However, when two or more adjacent / neighboring cells / sectors use the same Sub-cell-ID, PSS-aligned reference signals can cause conflicts between adjacent / neighboring cells / sectors and degrade cell search performance. Summary of the Invention

[0005] Embodiments of the disclosed technology include a physical layer subcell identity allocation method for selecting a subcell identity vector for a network device in a wireless network. In one embodiment, the method includes selecting a plurality of subcell identity vector candidates for the network device from a set of possible subcell identity vector candidates, wherein the network device has a plurality of sectors, each sector to be assigned a subcell identity within a subcell identity vector, and wherein the selection removes one or more possible subcell identity vector candidates that contain the same subcell identity for two or more adjacent sectors of the network device. The method also includes determining a plurality of conflict measurements for each of the plurality of subcell identity vector candidates, each conflict measurement being a metric that measures subcell identity conflicts between the plurality of sectors and one or more neighboring cells of the network device in the wireless network, each of the one or more neighboring cells belonging to another network device. The method then proceeds by deriving a single value from the plurality of conflict measurements for each of the plurality of subcell identity vector candidates; and selecting a subcell identity vector for the network device from the plurality of subcell identity vector candidates based on the single value.

[0006] Embodiments of the disclosed technology include an electronic device for physical layer sub-cell identity allocation to select a sub-cell identity vector for a network device in a wireless network. In one embodiment, the electronic device includes a processor and a non-transitory computer-readable storage medium providing instructions that, when executed by the processor, cause the electronic device to perform one or more methods for physical layer sub-cell identity allocation to select a sub-cell identity vector for a network device in a wireless network. One method includes selecting a plurality of sub-cell identity vector candidates for the network device from a set of possible sub-cell identity vector candidates, wherein the network device has a plurality of sectors, each sector to be assigned a sub-cell identity within a sub-cell identity vector, and wherein the selecting removes one or more possible sub-cell identity vector candidates that contain the same sub-cell identity for two or more neighboring sectors of the network device. The method also includes determining a plurality of conflict measurements for each of the plurality of sub-cell identity vector candidates, each conflict measurement being a metric that measures sub-cell identity conflict between the plurality of sectors and one or more neighboring cells of the network device in the wireless network, each of the one or more neighboring cells belonging to another network device. The method continues by deriving a single value from the plurality of conflicting measurements for each of the plurality of sub-cell identification vector candidates; and selecting a sub-cell identification vector for the network device from the plurality of sub-cell identification vector candidates based on the single value.

[0007] Embodiments of the disclosed technology include a non-transitory computer-readable storage medium for physical layer sub-cell identity allocation to select a sub-cell identity vector for a network device in a wireless network. In one embodiment, the non-transitory computer-readable storage medium provides instructions that, when executed, cause an electronic device to perform one or more methods for physical layer sub-cell identity allocation to select a sub-cell identity vector for a network device in a wireless network. One method includes selecting a plurality of sub-cell identity vector candidates for the network device from a set of possible sub-cell identity vector candidates, wherein the network device has a plurality of sectors, each sector to be assigned a sub-cell identity within a sub-cell identity vector, and wherein the selecting removes one or more possible sub-cell identity vector candidates that contain the same sub-cell identity for two or more neighboring sectors of the network device. The method also includes determining a plurality of conflict measurements for each of the plurality of sub-cell identity vector candidates, each conflict measurement being a metric that measures sub-cell identity conflict between the plurality of sectors and one or more neighboring cells of the network device in the wireless network, each of the one or more neighboring cells belonging to another network device. The method continues by deriving a single value from the plurality of conflicting measurements for each of the plurality of sub-cell identification vector candidates; and selecting a sub-cell identification vector for the network device from the plurality of sub-cell identification vector candidates based on the single value.

[0008] Embodiments of the disclosed technology provide electronic devices with a way to provide optimal physical layer sub-cell identity allocation, thereby improving the performance of the cell search process. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention may best be understood by referring to the following description and accompanying drawings which illustrate embodiments of the invention. In the drawings:

[0010] Figure 1 The physical layer identification (PCI) structure in long-term evolution (LTE) and fifth-generation cellular network technology (5G NR) is shown.

[0011] Figure 2 Exemplary timing of the PSS and SSS for LTE frequency division duplex (FDD) is shown.

[0012] Figure 3 Exemplary timing of the PSS and SSS for LTE time division duplex (TDD) is shown.

[0013] Figure 4 Example relative spacing of the PSS and SSS for 5G NR is shown.

[0014] Figure 5 An exemplary cell-specific reference signal (CRS) allocation in different subcarriers within a physical resource block (PRB) for LTE using different PSS in different sectors is shown.

[0015] Figure 6 FIG. 4 illustrates a Sub-cell-ID conflict between adjacent cells in a wireless network.

[0016] Figure 7 A Sub-cell-ID conflict between adjacent sectors of a network device in a wireless network is shown.

[0017] Figure 8 Sector neighbor conflict removal according to some embodiments of the present invention is shown.

[0018] Figure 9 The remaining Sub-cell-ID arrangement after removing sector neighbor conflicts is shown.

[0019] Figure 10 Determination of conflicting relative bearing measurements according to some embodiments of the present invention is shown.

[0020] Figure 11 Shown is a face factor measurement in degrees between two sectors according to some embodiments of the present invention.

[0021] Figure 12 Overlapping regions according to some embodiments of the present invention are shown.

[0022] Figure 13 A flow chart for collecting attributes of a geospatial node according to some embodiments of the present invention is shown.

[0023] Figure 14 An overlapping area is shown where buildings and roads are identified and measured, according to some embodiments of the present invention.

[0024] Figure 15 A table including multiple measurements for a set of Sub-cell-ID permutations according to some embodiments of the present invention is shown.

[0025] Figure 16 A table including normalized measurements for a set of Sub-cell-ID permutations according to some embodiments of the present invention is shown.

[0026] Figure 17 A table including normalized measures with calculated Sub-cell-ID conflict values ​​for a set of Sub-cell-ID permutations is shown according to some embodiments of the present invention.

[0027] Figure 18 is a flow chart illustrating operations at a network device for allocating physical layer sub-cell identities according to some embodiments of the present invention.

[0028] Figure 19 is a flow chart illustrating selection of a metric for measuring sub-cell identity conflicts according to some embodiments of the present invention.

[0029] Figure 20A Connectivity between network devices (NDs) within an exemplary network and three exemplary implementations of NDs are shown according to some embodiments of the present invention.

[0030] Figure 20B An example approach for implementing a dedicated network device according to some embodiments of the present invention is shown.

[0031] Figure 20C Various exemplary ways in which virtual network elements (VNEs) may be coupled according to some embodiments of the present invention are shown.

[0032] Figure 20D A network with a single network element (NE) on each ND according to some embodiments of the present invention is shown, in which a traditional distributed approach (commonly used by traditional routers) is compared with a centralized approach for maintaining reachability and forwarding information (also known as network control).

[0033] Figure 20E The following simple case according to some embodiments of the present invention is shown: each ND implements a single NE, and the centralized control plane abstracts (represents) multiple NEs in different NDs as a single NE in one of the virtual networks.

[0034] Figure 20F The following scenario is shown according to some embodiments of the present invention: multiple VNEs are implemented on different NDs and coupled to each other, and a centralized control plane abstracts the multiple VNEs so that they appear as a single VNE in one of the virtual networks.

[0035] Figure 21 A general control plane device with centralized control plane (CCP) software according to some embodiments of the present invention is shown. DETAILED DESCRIPTION

[0036] The following description describes a method and apparatus for allocating physical layer subcell identifiers in a wireless network. In the following description, numerous specific details are set forth, such as logic implementation, operation codes (opcodes), means for specifying operands, resource partitioning / sharing / replication implementations, types and relationships of system components, and logic partitioning / integration options, to provide a more comprehensive understanding of the present invention. However, those skilled in the art will appreciate that the present invention can be implemented without these specific details. In other examples, control structures, gate-level circuits, and full software instruction sequences are not shown in detail so as not to obscure the present invention. Using the included description, one of ordinary skill in the art will be able to implement the appropriate functionality without undue experimentation.

[0037] the term

[0038] References in the specification to "one embodiment," "an embodiment," "an example embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it should be understood that it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0039] In this document, text in brackets and boxes with dashed borders (e.g., long dash dot dash line, short dash dot dash line, dot dash line, and dot) may be used to illustrate optional operations that add additional features to embodiments of the present invention. However, such notation should not be taken to mean that in certain embodiments of the present invention, they are the only options or optional operations, and / or that boxes with solid borders are not optional.

[0040] In the following description and claims, the terms "coupled" and "connected," as well as their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. "Coupled" is used to indicate that two or more elements may or may not be in direct physical or electrical contact, cooperate, or interact with each other. "Connected" is used to indicate that communication is established between two or more elements that are coupled to each other.

[0041] Electronic devices use machine-readable media (also referred to as computer-readable media) to store and transmit (internally and / or over a network with other electronic devices) code (which consists of software instructions and is sometimes referred to as computer program code or computer programs) and / or data, such as machine-readable storage media (e.g., magnetic disks, optical disks, solid-state drives, read-only memory (ROM), flash memory devices, phase-change memory) and machine-readable transmission media (also referred to as carriers) (e.g., electrical, optical, radio, acoustic, or other forms of propagated signals - e.g., carrier waves, infrared signals). Thus, an electronic device (e.g., a computer) includes hardware and software, such as a collection of one or more processors (e.g., where the processor is a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), other electronic circuit, or a combination of one or more of the foregoing) coupled to one or more machine-readable storage media to store code for execution on the collection of processors and / or to store data. For example, an electronic device may include non-volatile memory containing code because non-volatile memory can retain code / data even when the electronic device is turned off (when power is removed). When an electronic device is turned on, the code portion to be executed by the (one or more) processors of the electronic device is typically copied from the slower non-volatile memory of the electronic device to a volatile memory (e.g., dynamic random access memory (DRAM), static random access memory (SRAM)). Typical electronic devices also include a set of one or more physical network interfaces (NIs) for establishing network connections with other electronic devices (to transmit and / or receive code and / or data using propagation signals). For example, the set of physical NIs (or the combination of the set of physical NIs and the set of processors that execute code) can perform any formatting, encoding, or conversion to allow the electronic device to send and receive data (via wired and / or wireless connections). In some embodiments, the physical NI may include a radio circuit capable of (1) receiving data from other electronic devices via a wireless connection and / or (2) sending data to other devices via a wireless connection. The radio circuit may include a transmitter, a receiver, and / or a transceiver suitable for radio frequency communication. The radio circuit can convert digital data into a radio signal with suitable parameters (e.g., frequency, timing, channel, bandwidth, etc.). The radio signal can then be transmitted to an appropriate recipient via an antenna. In some embodiments, the collection of physical NIs may include a network interface controller (NIC), also known as a network interface card, network adapter, or local area network (LAN) adapter. A NIC can facilitate connecting electronic devices to other electronic devices by plugging a cable into a physical port connected to the NIC, thereby allowing them to communicate via wired communication. One or more portions of embodiments of the present invention may be implemented using various combinations of software, firmware, and / or hardware.

[0042] A wireless communication network (also known as a cellular network) is a network of devices that use radio waves (electromagnetic waves with a frequency of 30KHz-300GHz) to communicate. Wireless communication can follow wireless communication standards such as New Radio (NR), LTE (Long Term Evolution), Advanced LTE (LTE-A), Wideband Code Division Multiple Access (WCDMA), and High Speed ​​Packet Access (HSPA). In addition, communication between electronic devices such as network devices and terminal devices in the wireless communication network can be performed according to any communication protocol suitable for a generation, including but not limited to first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols and / or any other protocol currently known or to be developed in the future. Although LTE and NR are used as examples to describe the embodiments of the present disclosure, the present disclosure can be applied to other wireless communication networks, including LTE operating in unlicensed spectrum, Multifire systems, and Institute of Electrical and Electronics Engineers (IEEE) 802.11 systems.

[0043] A network device (ND) (also referred to as a network node or node, these terms are used interchangeably in this disclosure unless otherwise specified) is an electronic device in a wireless communication network, via which a terminal device accesses the network and receives services from the network. Examples of network nodes include access points (APs), NodeBs, base stations (BSs), multi-standard radio (MSR) radio nodes such as MSR BSs, evolved NodeBs (eNodeBs or eNBs), next generation NodeBs (gNBs), master base stations (MeNBs), secondary base stations (SeNBs), network controllers, radio network controllers (RNCs), core network nodes (e.g., nodes for access and mobility management functions (AMFs), mobility management entities (MMEs), mobile switching centers (MSCs), etc.), base station controllers (BSCs), roadside units (RSUs), relays, donor nodes that control relays, base transceiver stations (BTSs), transmission points, transmission nodes, remote radio units (RRUs), remote radio heads (RRHs), nodes in distributed antenna systems (DASs), operations and management (O&M) systems, operations support systems (OSSs), self-organizing networks (SONs), positioning nodes (e.g., enhanced serving mobile positioning centers (E-SMLCs)), etc. One type of network device may be a low-power node such as a femtocell and a picocell.

[0044] The terminal device can access the wireless communication network and receive services from the wireless communication network through the network device. The terminal device may also be referred to as a wireless device (WD), and the two terms are used interchangeably in this disclosure. The terminal device may be a user equipment (UE), which may be a subscriber station, a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may be one of a mobile phone, a cellular phone, a smart phone, a tablet computer, a wearable device, a personal digital assistant (PDA), a portable computer, an image capture terminal device such as a digital camera, a game terminal device, a music storage and playback device, a vehicle-mounted wireless terminal device, a smart speaker, a set-top box, and a customer premises equipment (CPE). Note that although UE is often used as an example of a terminal device in this disclosure, embodiments of the present disclosure are also applicable to other terminal devices.

[0045] A cell site (also known as a cell tower, cellular base station, or simply a site) is a cellular-enabled network equipment site where antennas and network equipment are placed (typically on a radio pole, tower, or other raised structure) to create a cell in a wireless network. Although historically antennas were omnidirectional, directional antennas are now common. One or more antennas can cover one sector of a cell site (or cell), and all antennas cover the applicable direction of the cell site. Therefore, the network equipment at a cell site can have multiple sectors, each covering one cell. Although current network equipment at cell sites typically has three to six sectors, in future deployments, more sectors may be added to each site (and / or each network equipment). Embodiments of the present invention are not limited by the number of sectors supported by the network equipment at the cell site.

[0046] The physical layer identifier (PCI) can identify the sector / cell of the network equipment at the cell site in the physical layer. The PCI can be expressed as a combination of a physical layer cell identifier group (referred to as a PCI group, typically represented by physicalLayerCellIdGroup) and a physical layer sub-cell identifier (interchangeably referred to as PCI-ID, PCI-Sub-cell-ID, Sub-cell-ID, or Subcell ID, and typically represented by physicalLayerSubCellId). The physical layer cell identifier group and the physical layer sub-cell identifier are derived from the secondary synchronization signal (SSS) and the primary synchronization signal (PSS), respectively. For example, a formula for determining the PCI is as follows: PCI = [3*physicalLayerCellIdGroup] + physicalLayerSubCellId.

[0047] A subcell identification vector is a vector representing the sector subcell identifications of a network device with multiple sectors. For a network device with three sectors, its subcell identification vector has three data elements; for a network device with four sectors, its subcell identification vector has four data elements; and so on. Some existing standards restrict subcell identifications to integers in the range of 0 to 2. Thus, the subcell identification vector for a network device with three sectors may be [0, 1, 2]; the subcell identification vector for a network device with four sectors may be [0, 1, 2, 1]; and so on. Embodiments of the present invention are not limited to a specific range of subcell identification values.

[0048] Physical Layer Identification (PCI) Planning and Challenges

[0049] Figure 1 The physical layer identifier (PCI) structure in Long Term Evolution (LTE) and fifth generation cellular network technology, New Radio (5G NR, or simply 5G, NR, and these terms are used interchangeably in this disclosure) is shown. In LTE, the PCI at reference numeral 152 is in the range of 0 to 502, while in 5G NR, the PCI at reference numeral 154 is in the range of 0 to 1008. The physical layer cell identifier group physicalLayerCellIdGroups (in the range of 0 to 167 for LTE and in the range of 0 to 335 for 5G NR) and the physical layer subcell identifier physicalLayerSubCellIds (in the range of 0 to 2) are derived from the secondary synchronization signal (SSS) and the primary synchronization signal (PSS), respectively. In this example, the formula PCI = [3*physicalLayerCellIdGroup] + physicalLayerSubCellId is applicable to both LTE and 5G NR.

[0050] Figure 2 Example timing of the PSS and SSS for LTE frequency division duplex (FDD) is shown. This example assumes a normal cyclic prefix, as there are seven symbols in each slot. The SSS and PSS are within the last two symbols of the slot, as shown at 202 and 204. The extended cyclic prefix follows a similar pattern, except that there are only six symbols in the slot.

[0051] Figure 3Example timing of the PSS and SSS for LTE time division duplex (TDD) is shown. This example assumes a normal cyclic prefix, uplink-downlink subframe configuration 0, and special subframe configuration 0. The SSS is within the last symbol of slots 1 and 11 (shown at reference numerals 302 and 304, respectively), while the PSS is within the third symbol of slots 2 and 12 (shown at reference numerals 312 and 314, respectively). The extended cyclic prefix follows a similar pattern, except that there are only 6 symbols in the slot.

[0052] Note that although 6 and 7 symbols per time slot are used as examples to illustrate embodiments of the present invention, it should be understood by those skilled in the art that other numbers of symbols per time slot can be implemented in embodiments of the present invention (for example, 14 symbols per time slot is also widely used).

[0053] Figure 4 Figure 405 shows an example relative spacing of the PSS and SSS for 5G NR. Unlike LTE, the LTE PSS is mapped to the central 72 subcarriers, while the NR PSS is mapped to the 127 active subcarriers at 402, and the frequency at which the PSS is transmitted depends on the synchronization signal (SS) burst periodicity.

[0054] For both LTE and 5G NR, Sub-cell-ID allocation defines the alignment of reference signal or data resource elements (REs) between neighboring cells. Figure 5 An exemplary cell-specific reference signal (CRS) allocation in different subcarriers within a physical resource block (PRB) of LTE using different PSSs in different sectors is shown. Adjacent sectors (sectors 1 to 3 at reference numerals 502 to 506) use different PSSs, and CRSs are allocated in different subcarriers within the PRB. Different physical layer subcell identifiers avoid conflicts between adjacent sectors of the same network device or between adjacent sectors / cells.

[0055] Existing PCI planning methods typically aim to maximize PCI reuse distance to reduce PCI conflicts. For example, they can identify appropriate PCIs (e.g., random assignment) or PCI groups (e.g., in MOD 3 or 6 planning) to produce the maximum PCI reuse distance. However, these methods do not address the PSS interference issue, which can affect terminal device performance when a terminal device receives signals from two different cells / sectors with the same Sub-cell-ID.

[0056] Figure 6FIG. 6 illustrates a Sub-cell-ID conflict between adjacent cells in a wireless network. The wireless network 600 includes three network devices (NDs) at reference numerals 652, 654, and 656 and a terminal device (TD) at reference numeral 658 served by these NDs. Each of the three network devices 652 to 656 has three sectors (cells). The sectors of ND 654 are identified as cells 1 to 3, while the sectors of ND 656 are identified as cells 4 to 6. Each sector has a unique PCI, and the PCI allocation table at reference numeral 622 shows the PCI allocations for NDs 654 and 656. As shown, Sub-cell-ID is an integer in the range of 0 to 2. The sub-cell identification vectors of NDs 654 and 656 are both [0, 1, 2]. Based on the PCI allocation, cells 1 and 4 have the same sub-cell identification, Sub-cell-ID=0. The CRSs of cells 1 and 4 are allocated in the same subcarriers, as shown at reference numerals 602 and 604. At TD 658, it receives reference signals from both cells 1 and 4 having the same Sub-cell-ID, as shown at reference numerals 632 and 634. The reference signals from cells 1 and 4 collide, and this collision degrades the cell search performance of TD 658.

[0057] Signal collisions occur not only between adjacent cells of different network devices, but also between adjacent sectors of the same network device. For example, when a network device has more than three sectors and the Sub-cell ID has only three values, adjacent sectors may be assigned the same Sub-cell ID, resulting in collisions. Figure 7 FIGURE 7 illustrates a Sub-cell ID conflict between adjacent sectors of a network device in a wireless network. A PCI is to be assigned to a network device at a cell site 750. The network device will have four sectors, with a Sub-cell ID assigned to each sector. It is determined that the candidate PCI groups include PCI groups 139 and 141. Given that each PCI group has only three unique Sub-cell IDs (0, 1, and 2), both PCI groups 139 and 141 will be assigned to the site. The problem is to find the best performing Sub-cell ID assignment, as shown at 702.

[0058] Existing PCI planning methods can recommend the best four PCIs for four sectors or recommend two best PCI groups based on the optimal PCI reuse distance. For example, existing PCI planning methods can implement the PCI allocation shown in PCI allocation table 722. However, as shown at reference numeral 704, the PCI allocation using the optimal PCI reuse distance causes two adjacent sectors to have the same Sub-cell ID, and the same Sub-cell ID of the two adjacent sectors causes PSS interference.

[0059] Assigning the same Sub-cell-ID to adjacent sectors of the same network device or adjacent cells of different network devices is detrimental to the cell search process. The resulting PSS interference affects all subsequent processes (e.g., initial access or handover) and associated performance indicators (e.g., maintainability), and the impact includes longer delays and / or lower success rates. For example, delays or failures in the cell search process during handover will interrupt or affect user-plane data flows, thereby affecting the end-user experience. In addition, measured service-level key performance indicators (KPIs) will also be negatively affected.

[0060] The deployment of network equipment with multiple sectors is increasing. For LTE deployments, all service providers are focusing on adding sectors and further densification in existing sites to improve the end-user experience and increase LTE user throughput. As a result, the inter-site distance is shortened and sites with more than three sectors are increasing, especially for sites serving areas where capacity increases are needed. For 5G NR deployments, due to the relatively higher frequencies of 5G (e.g., >6 GHz), the achievable cell radius will decrease again and thus shorten the inter-site distance.

[0061] The complexity of PSS interference increases as the number of sectors increases. For example, for a 4-sector site, assuming that the Sub-cell-ID has three possible values, there are 81 possible permutations (3×3×3×3=81) of Sub-cell-ID allocation (i.e., 81 sub-cell identity vector candidates per site). For a 5-sector site, the number increases to 243.

[0062] However, no existing PCI planning method can optimize physical layer sub-cell ID allocation to improve the performance of the cell search process. Manual physical layer sub-cell ID allocation is time-consuming due to the large number of permutations that need to be calculated. When deploying large numbers of network devices with multiple sectors (e.g., four to six sectors per site), this manual process is difficult to scale appropriately.

[0063] Embodiment of physical layer sub-cell identity allocation

[0064] Embodiments of the present invention provide an automated method for identifying the optimal subcell identification vector for a network device with multiple sectors. In one embodiment, subcell identification vector candidates with adjacent conflicts are removed from possible subcell identification vector candidates for a network device at a site. A conflict measurement for neighboring cells is then determined for the remaining subcell identification vector candidates. Finally, the optimal subcell identification vector for the network device is identified based on this measurement. Each of these operations is described in more detail below.

[0065] Note that embodiments of the present invention do not modify existing standards or system specifications for wireless networks. In fact, their implementation can complement existing PCI planning methods. For example, existing PCI planning methods can be used to identify PCI groups for network devices with multiple sectors, while embodiments of the present invention can be used to identify the optimal Sub-cell-ID. Figure 7 In the embodiment, existing PCI planning methods can be used to identify PCI groups 141 and 139 (for example, because they provide the best PCI reuse distance), while embodiments of the present invention are used to identify the best sub-cell identification vector (for example, [0, 2, 0, 1]), where the first data element, the second data element, and the fourth data element of the vector are mapped to PCI group 141, and the third data element is mapped to PCI group 139.

[0066] Since the Sub-cell-ID value is limited to a very limited range (e.g., 3 values ​​such as 0 to 2), the quantitative method adopted by the embodiments of the present invention may not completely alleviate the PSS interference caused by Sub-cell-ID conflicts. However, minimizing PSS interference is still important in PCI planning and becomes more important as the density of network devices with a large number of sectors in wireless networks (LTE, 5G NR, etc.) continues to increase.

[0067] Eliminate sector adjacent conflicts

[0068] Figure 8 Sector proximity conflict resolution according to some embodiments of the present invention is illustrated. To deploy a network device with multiple sectors at a cell site, PCI planning may begin with all possible Sub-cell-ID permutations at reference numeral 802, where each permutation is a sub-cell identification vector for the network device.

[0069] As mentioned above, for a network device with four sectors, there are 81 possible permutations of Sub-cell-ID allocation. However, not all permutations are efficient in terms of PCI group allocation. For example, a possible sub-cell identification vector is [0, 0, 0, 0], which will consume four PCI group numbers, one for each data element of the vector. Obviously, a network device with four sectors occupying four PCI group numbers is inefficient for achieving the optimal PCI reuse distance. In fact, for a network device with four sectors, any sub-cell identification vector that maps to more than two PCI groups is inefficient for PCI group allocation, because each PCI group has three Sub-cell-IDs, and two PCI groups are sufficient to distinguish Sub-cell-IDs. Therefore, permutations that consume more than two PCI group numbers can be removed.

[0070] After removal, the remaining sub-cell-ID permutations are shown at 804, and each remaining sub-cell-ID permutation uses only two PCI group numbers. For example, if the first sub-cell identification vector is [0, 2, 0, 1] (at 804), its second to fourth data elements can be mapped to one PCI group, while the first data element is mapped to the second PCI group. Existing PCI planning methods can be used to achieve PCI group optimization.

[0071] Then, the remaining Sub-cell-ID permutations are checked to remove sector adjacent conflicts. When the same Sub-cell-ID value is assigned to two or more adjacent sectors, it will cause PSS interference as described above. Figure 7 As illustrated. Therefore, it is necessary to remove the Sub-cell-ID arrangement with sector neighbor conflicts. For example, at reference numeral 804, the second sub-cell identification vector is [0, 1, 1, 2], and the neighboring sectors mapped to the second and third data elements have the same Sub-cell-ID value 1, so they need to be removed. As shown at reference numeral 852, the third to sixth sub-cell identification vectors need to be processed in the same way. After removing the sector neighbor conflicts, the updated Sub-cell-ID arrangement is shown at reference numeral 806. As shown in the figure, the removal reduces the Sub-cell-ID arrangements from 36 at reference numeral 804 to 12 at reference numeral 806. The removal can be implemented in a computer program (e.g., a Python function or a function in another computer program). Figure 9 The updated Sub-cell-ID arrangement is shown.

[0072] Determine adjacent cell conflicts

[0073] Then, the updated Sub-cell-ID arrangement can be further checked to reduce the conflict between adjacent cells. Figure 6As shown in the related discussion, a neighboring cell may be assigned the same Sub-cell-ID as a sector of a network device and cause PSS interference. This PSS interference also occurs when the sector and the neighboring cell transmit at the same frequency. Existing methods can be used to measure the transmission frequency. For example, the absolute radio frequency channel number (ARFCN) in the Global System for Mobile Communications (GSM) network can be used to determine the transmission frequency of a sector or cell. It can be determined using the UTRA Absolute Radio Frequency Channel Number (UARFCN) in LTE (where UTRA stands for Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access) or the Evolved UTRA (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN). When two cells / sectors have the same ARFCN / UARFCN / EARFCN number, they are considered to be transmitting at the same frequency.

[0074] A neighboring cell or a sector of a neighboring cell having the same Sub-cell-ID and the same frequency as a sector of a network device to which a PCI is assigned may be referred to as a conflicting neighboring cell. Note that a conflicting neighboring cell includes a conflicting neighboring "sector" located at a site having multiple sectors, and only one (or more) sectors (not the entire site) conflict with a sector of a network device.

[0075] Several metrics may be used to compare the interference levels of possible Sub-cell-ID permutations and determine the optimal Sub-cell-ID assignment, which are described in more detail below.

[0076] Number of conflicts

[0077] This metric measures the number of neighboring cells with the same Sub-cell ID and frequency as the sector of the network device to which the PCI is assigned. To derive this number, first-level neighbor polygons are identified. First-level neighbors are the closest neighboring cells in a given direction. Based on these first-level neighbor polygons, the number of conflicting Sub-cell IDs between the network device's sector and its first-level neighbors can be calculated.

[0078] Conflicting distance measurements

[0079] For a given conflict identified in determining the number of conflicts, the distance between the network device's site and the conflicting neighboring cell / sector can be determined. A measure can be taken to account for all distance measurements of the conflict. For example, the sum of the distances, the average distance, the median distance, the maximum distance, and / or the minimum distance can be calculated as an overall measure of the distance of the conflict.

[0080] Relative bearing measurement of conflicts

[0081] For a given collision determined in the collision number determination, the relative position between the sector of the network device and the collision neighboring cell / sector may be determined.

[0082] Figure 10 The determination of conflicting relative bearing measurements according to some embodiments of the present invention is shown. Figure 10 In FIG. 1 , a first level neighbor polygon 1002 is identified, centered at a site 1050 implementing a network device having multiple sectors. The sector's position is compared to the position of the conflicting neighboring cell, and the relative position is the difference between the two positions.

[0083] For example, the sector bearing of the Sub-cell ID of the planned network device is shown at reference numeral 1020, and the conflicting neighboring cell of a sector with the same Sub-cell ID is shown at reference numeral 1052. The sector bearing of the conflicting neighboring cell of this sector is shown at reference numeral 1022. The difference between these two bearings is the relative bearing of the conflict, as shown at reference numeral 1060. In this example, the relative bearing is -22.2°. Obviously, the relative bearing can also be measured in radians.

[0084] A measure may be taken to take all relative bearing measurements of a conflict into account, for example, the sum of the relative bearing measurements, the average relative bearing measurement, the median relative bearing measurement, the maximum relative bearing measurement and / or the minimum relative bearing measurement may be calculated as an overall measure of the relative bearing measurements of the conflict.

[0085] Conflict Confrontation Factor Measurement

[0086] For a given conflict determined in the conflict number determination, a facing factor between the sector of the network device and the conflicting neighboring cell / sector can be determined. The facing factor is a metric that identifies whether two sectors are facing each other. The facing factor can be measured in a range of 0 to 180 degrees (or 0 to π radians), with the higher the value, the more the two sectors face each other.

[0087] Figure 11 1 shows a facing factor measurement in degrees between two sectors according to some embodiments of the present invention. In an example with a facing factor of 90 degrees, a conflicting sector of a network device in a PCI plan has a sector orientation as shown at reference numeral 1120, and a conflicting adjacent sector has a sector orientation as shown at reference numeral 1122, while the facing factor is measured as 90 degrees as shown at reference numeral 1102.

[0088] A measure can be taken to take into account all the conflicting factor measures. For example, the sum of the conflicting factor measures, the average conflicting factor measure, the median conflicting factor measure, the maximum conflicting factor measure, and / or the minimum conflicting factor measure can be calculated as an overall measure of the conflicting factor measures.

[0089] Measurement of overlapping areas and associated building areas and route lengths

[0090] For a given conflict identified in determining the number of conflicts, an overlap area between a sector of the network device and the conflicting neighboring cell / sector can be determined. The size of the overlap area between the sector and the cell / sector is a measure of the interference level. A measure can be taken that takes into account all overlap area measurements for the conflict. For example, a sum of the overlap area measurements, an average overlap area measurement, a median overlap area measurement, a maximum overlap area measurement, and / or a minimum overlap area measurement can be calculated as an overall measure of the overlap area for the conflict.

[0091] Figure 12 An overlapping area according to some embodiments of the present invention is shown in FIG. A cell site 1250 and a conflicting neighboring cell 1252 have sectors with the same Sub-cell-ID, and the beam coverage of these two sectors overlap, as shown in the overlapping area 1202 .

[0092] In one embodiment, an overshooting factor of 0.8 is considered to estimate the overlap area, where the overshooting factor is defined as the ratio of the average service radial distance of the sector to the first layer neighbor distance. The first layer neighbor distance is the average distance between the site and the first layer neighbors within a given direction / azimuth range. The overshooting factor can be set to different values ​​to achieve different overlap areas between the sector and the neighboring cells / sectors. For example, the overshooting factor can be adjusted based on the average inter-site distance of a given cluster. A cluster is a group of cells covering an area (for example, seven cells forming a cluster covering the area), and the inter-site distance is the distance between the cells of the cluster.

[0093] After determining the overlapping area, geospatial nodes (objects) within the area that may affect communication are determined, and this determination uses map data for the area. This map data can be obtained using different maps that may be used by different applications / programs. For example, OpenStreetMap (OSM), a collaborative project that creates a free, editable world map, can be used; other proprietary maps can also be used. Figure 13 A flow chart for collecting attributes of a geospatial node according to some embodiments of the present invention is shown.

[0094] Operations begin at reference numeral 1302, where a polygon object is derived based on the overlap area between two sectors / cells. This derivation is based on the latitude and longitude of the overlap area. Then, at reference numeral 1304, a bounding box is defined using location data (e.g., the minimum and maximum latitude and longitude from the polygon object).

[0095] At reference numeral 1306, a map database system 1355 is queried to obtain the geospatial nodes and attributes within the bounding box at reference numeral 1306. The map database system 1355 can be an open source system (e.g., OSM), a proprietary system, or a combination thereof. The map database system 1355 includes a geospatial database 1352 and an interface 1354 through which the geospatial database 1352 is queried.

[0096] At reference numeral 1308, the edges of the geospatial nodes outside the polygon objects defining the overlap area are removed. Then, at reference numeral 1310, the attributes of each node are calculated and aggregated for each geospatial node type. Geospatial node types include building structures (e.g., various types of buildings), paths / roads, and terrain (e.g., mountains and valleys).

[0097] For each node geospatial node type, one or more measurements are aggregated. For example, for building structures, area measurements (e.g., in square meters or square miles) of the building structures within the overlap region can be aggregated into one building area measurement for the overlap region. For paths / roads, length measurements (e.g., in meters or miles) of the paths / roads that pass through the overlap region can be aggregated into one route length measurement for the overlap region. For each of the building structures and paths / roads, a single measurement that takes into account all conflicting overlapping area measurements can be: the sum of the corresponding area / length measurements, the average, median, maximum, and / or minimum of the area and length measurements.

[0098] Metrics such as building area and route length are important for prioritizing one conflict over another with respect to possible interference. Figure 12 An overlapping area 1202 is shown where there are no known building structures or paths / roads. In contrast, Figure 14 14. An overlap region is shown in which buildings and roads are identified and measured, according to some embodiments of the present invention. As shown at 1402, the overlap region 1402 is located between a cell site 1450 and its conflicting neighboring cell 1452. Multiple buildings are identified in the overlap region (as shown at 1422), and a road is identified (as shown at 1424).

[0099] The building area measurements are aggregated into a single building area measurement, which in this example is 38601.54 square meters (reference numeral 1432). The route length measurements are aggregated into a single route length measurement, which in this example is 159.642 meters (reference numeral 1434).

[0100] For reducing sub-cell-ID conflicts, overlap region 1402 is more important than overlap region 1202 because the former has a much higher probability of containing mobile users and the potential data generation volume should also be much higher. Therefore, using a single building area measurement and a single route length measurement (e.g., the measurements shown at reference numerals 1432 and 1434), the relative impotency of different overlap regions can be determined.

[0101] Identify the best subcell identification vector

[0102] The metrics discussed above are used to compare the interference levels of possible sub-cell-ID permutations and determine the optimal sub-cell-ID assignment. One way to use the measurements obtained above (e.g., a single measurement for each factor) is to derive a single value from all the measurements for each candidate (e.g., the remaining sub-cell-ID permutation candidates obtained at reference numeral 806) and use that single value to find the optimal sub-cell-ID assignment. This process includes metric selection, measurement normalization, and quantitative selection.

[0103] Metric selection

[0104] Figure 15 1522 includes a table of multiple measurements for a set of Sub-cell-ID permutations according to some embodiments of the present invention. Figure 8 The measurement of the Sub-cell-ID permutation set at reference numeral 806 of FIG. At column 1502 , the indexes of the Sub-cell-ID permutations are 0 to 11, and the Sub-cell-ID permutations (sub-cell identification vectors) are listed at column 1504 .

[0105] Columns 1506 to 1516 show a set of metrics and corresponding measurements for each Sub-cell-ID arrangement. The metric set includes the number of conflicts (Conflict_Count) at reference numeral 1506, the average distance of conflicts (Distance_Meter_mean) at reference numeral 1508, the average relative orientation of conflicts (Relative_Orientation_mean) at reference numeral 1510, the average face factor of conflicts (Face_Factor_mean) at reference numeral 1512, the total building area of ​​the overlapping area in square meters (Building_Area_Sqrm_sum) 1514, and the total route length of the overlapping area in meters (Route_Length_meter_sum) 1516.

[0106] Note that although this table includes averages and sums of metrics, other embodiments may use medians, minimums, maximums, or other arithmetic operations for conflict measurements. Furthermore, other embodiments may use more or fewer metrics when selecting the optimal Sub-cell-ID arrangement. For example, although this table does not include an overlap area metric, other embodiments may include that metric and other metrics known in the art.

[0107] Measurement normalization

[0108] After measurements for a set of metrics are collected, they are normalized. Figure 16 A table including normalized measurements for a set of Sub-cell-ID permutations according to some embodiments of the present invention is shown. Normalized collision measurement table 1622 is similar to collision measurement table 1522, having the same Sub-cell-ID permutation index 1502 and Sub-cell-ID permutation 1504, but the measurements are normalized (also referred to as "scaled," and the two terms are used interchangeably) to a range from 0 to 1 or from 1 to 0, based on the effects of the metrics shown in columns 1606 to 1616.

[0109] For example, the number of collisions is normalized to a range from 0 to 1 (lower is better because PSS interference will decrease with fewer collisions), and the average distance of collisions is normalized to a range from 1 to 0 (higher is better because PSS interference will decrease when the collision neighboring cells are farther apart).

[0110] Although the normalization uses the range of [0, 1] as an example, other ranges may be implemented in embodiments of the present invention.

[0111] Quantitative selection

[0112] Normalized measures of the various metrics can be combined to obtain a single interference metric for the Sub-cell-ID arrangement. Figure 17 17 shows a table including a normalized measure with calculated sub-cell-ID conflict values ​​for a set of sub-cell-ID permutations according to some embodiments of the present invention. Normalized conflict measure table 1722 with calculated ID conflict values ​​is similar to normalized conflict measure table 1622 with the addition of row 1702 indicating the final score for each sub-cell-ID permutation in the set of sub-cell-ID permutations.

[0113] In this example, the score of the sub-cell-ID permutation is simply the sum of the normalized measures of the metrics considered. The sub-cell-ID permutation with the lowest score is selected as the best sub-cell-ID permutation that is deemed to cause the least overall PSS interference, as shown by reference numeral 1750. The best sub-cell-ID permutation is [0, 1, 2, 1].

[0114] While this example uses the sum of normalized measurements to select the optimal Sub-cell-ID arrangement, other arithmetic operations can also be used for this quantitative selection. For example, different weights can be applied to different metrics so that for a given scenario, more important metrics can be given higher priority than less important metrics. By adjusting the weights, embodiments of the present invention can be flexible enough to cover a variety of scenarios.

[0115] Additionally, while this example selects the Sub-cell-ID arrangement with the smallest score as the selected target, some embodiments may select the maximum value of a different score derived from another set of metrics to select the Sub-cell-ID arrangement.

[0116] Some embodiments

[0117] The operations in the flowcharts may be described with reference to the example embodiments of the other drawings. However, it should be understood that the operations in the flowcharts may be performed by embodiments of the present invention other than those described with reference to the other drawings, and that the embodiments of the present invention discussed with reference to these other drawings may perform operations different from those discussed with reference to the flowcharts.

[0118] Figure 181800 is a flow chart illustrating operations for allocating physical layer sub-cell identifiers at a network device according to some embodiments of the present invention. The network device is to be deployed (or has already been deployed) at a cell site, where the network device has multiple sectors (e.g., the cell site or the network device has multiple directional antennas, each covering a direction). The physical layer sub-cell identifier allocation of method 1800 may be performed by the network device, or by an electronic device outside the network device that is designated to perform physical layer sub-cell identifier allocation.

[0119] Optionally, at reference numeral 1802, a set of possible sub-cell identification vector candidates is determined based on the multiple sectors of the network device. In one embodiment, the set of possible sub-cell identification vector candidates may include all possible sub-cell-ID permutations, as shown at reference numeral 802. Alternatively, the set of possible sub-cell identification vector candidates is the set of sub-cell identification vector candidates after removing sub-cell-ID permutations with inefficient PCI group allocation, as shown at reference numeral 804.

[0120] At reference numeral 1804, a plurality of subcell identification vector candidates are selected for a network device from a set of possible subcell identification vector candidates, wherein the network device has the plurality of sectors, each sector to be assigned a subcell identification within the subcell identification vector, and wherein the selection removes one or more possible subcell identification vector candidates that contain the same subcell identification for two or more adjacent sectors of the network device. This operation removes sector neighbor conflicts, details of which are described above with respect to Figures 8 and 9 A discussion was held.

[0121] At reference numeral 1806, a plurality of conflict measurements are determined for each of the plurality of sub-cell identification vector candidates, each conflict measurement being a metric measuring a sub-cell identification conflict between the plurality of sectors and one or more neighboring cells of the network device in a wireless network, each of the one or more neighboring cells belonging to another network device. Figures 10 to 14 And the following Figure 19 The selection of these multiple conflicting measures is discussed.

[0122] At reference numeral 1808, a single value is derived from the plurality of conflicting measurements for each of the plurality of sub-cell identification vector candidates. At reference numeral 1810, a sub-cell identification vector for a network device is selected from the plurality of sub-cell identification vector candidates based on the single value.

[0123] In one embodiment, the deriving of the single value includes normalizing each of the plurality of conflict measurements to be within the same value range and combining the plurality of conflict measurements into the single value after normalization. In one embodiment, the combining of the plurality of conflict measurements uses different weights for at least a subset of the plurality of conflict measurements.

[0124] about Figures 15 to 17 The derivation of this single value and the selection of the sub-cell identification vector (including normalization and combining) are discussed in more detail.

[0125] Figure 19 is a flow chart illustrating selection of a metric for measuring sub-cell identity conflicts according to some embodiments of the present invention. The operation at reference numeral 1806 includes selecting one or more metrics that quantify sub-cell identity conflicts.

[0126] The metrics include one or more of the metrics shown at reference numerals 1902 to 1914: a number of conflicts between the multiple sectors and the one or more neighboring cells at reference numeral 1902; a distance measurement of the number of conflicts at reference numeral 1904; a relative orientation measurement of the number of conflicts at reference numeral 1906; a facing factor measurement of a facing factor between the multiple sectors and the one or more neighboring cells at reference numeral 1908, wherein the facing factor measures the relative orientation between the sector and the neighboring cell; a size measurement of one or more overlapping areas between the multiple sectors and the one or more neighboring cells at reference numeral 1910; a route length measurement of a route length in the one or more overlapping areas between the multiple sectors and the one or more neighboring cells at reference numeral 1912; and a size measurement of a building area in the one or more overlapping areas between the multiple sectors and the one or more neighboring cells at reference numeral 1914.

[0127] Embodiments of the present invention provide automated radio network physical resource planning techniques enhanced with geospatial data to achieve the best possible sub-cell-ID allocation planning by quantitatively evaluating and prioritizing possible conflicts using a set of metrics, thereby improving the cell search process during initial access and mobility in wireless network deployments (e.g., LTE, 5G NR, and later systems).

[0128] Advantages of embodiments of the present invention include the following: reducing the probability of Sub-cell-ID-based conflicts; improving the cell search process and having a positive impact on subsequent events and processes; improving the accessibility, maintainability and mobility KPIs of service-level agreements; and supplementing / enhancing existing PCI planning methods.

[0129] Furthermore, embodiments of the present invention can be implemented distributedly across different network devices or cell sites with multiple sectors, or centrally at the electronic device responsible for managing the wireless network. They can be implemented as software packages integrated with other applications. Furthermore, embodiments of the present invention are vendor / carrier independent, and any vendor or carrier can use these embodiments for PCI planning. By eliminating the manual evaluation of all possible Sub-cell-ID permutations, PCI planning using embodiments of the present invention is scalable and efficient.

[0130] Network environment in which embodiments of the present invention can operate

[0131] Figure 20A Connectivity between network devices (NDs) within an exemplary network and three exemplary implementations of NDs are shown according to some embodiments of the present invention. Figure 20A NDs 2000A to 2000H are shown, along with their connectivity via lines between 2000A-2000B, 2000B-2000C, 2000C-2000D, 2000D-2000E, 2000E-2000F, 2000F-2000G, and 2000A-2000G, as well as connectivity between 2000H and each of 2000A, 2000C, 2000D, and 2000G. These NDs are physical devices, and connectivity between them can be wireless or wired (often referred to as links). Additional lines extending from NDs 2000A, 2000E, and 2000F illustrate that these NDs serve as entry and exit points for the network (and thus are sometimes referred to as edge NDs; other NDs may be referred to as core NDs).

[0132] Figure 20A Two exemplary ND implementations in are: 1) a dedicated network device 2002, which uses a custom application-specific integrated circuit (ASIC) and a proprietary operating system (OS); and 2) a general-purpose network device 2004, which uses a common off-the-shelf (COTS) processor and a standard OS.

[0133] The dedicated network device 2002 includes networking hardware 2010, which includes a set of one or more processors 2012, forwarding resources 2014 (which typically include one or more ASICs and / or network processors), and physical network interfaces (NIs) 2016 (through which network connections are made, such as shown by the connections between NDs 2000A-H), as well as non-transitory machine-readable storage media 2018 having stored therein networking software 2020. During operation, the networking software 2020 can be executed by the networking hardware 2010 to instantiate a set of one or more networking software instances 2022. Each networking software instance 2022 and the portion of the networking hardware 2010 that executes the networking software instance (if it is hardware dedicated to the networking software instance and / or a time slice of hardware that is time-shared by the networking software instance with other networking software instances 2022) form a separate virtual network element 2030A-2030R. Each virtual network element (VNE) 2030A-2030R includes a control communication and configuration module 2032A-2032R (sometimes referred to as a local control module or control communication module) and forwarding tables 2034A-2034R, such that a given virtual network element (e.g., 2030A) includes a control communication and configuration module (e.g., 2032A), a set of one or more forwarding tables (e.g., 2034A), and the portion of the networking hardware 2010 that executes the virtual network element (e.g., 2030A). In one embodiment, the networking software 2020 includes a PCI planner 2055 that executes the instructions described herein with respect to the PCI planner. Figure 18-19 The operations discussed. PCI planner 2055 may be instantiated as PCI planner instances 2044 and 2045 within virtual network elements, as shown.

[0134] The dedicated network device 2002 is often viewed physically and / or logically as comprising: 1) an ND control plane 2024 (sometimes referred to as the control plane), including a processor 2012 that executes control communications and configuration modules 2032A-2032R; and 2) an ND forwarding plane 2026 (sometimes referred to as the forwarding plane, data plane, or media plane), including forwarding resources 2014 and physical NIs 2016 that utilize forwarding tables 2034A-2034R. As an example of ND being a router (or implementing routing functions), the ND control plane 2024 (processor 2012 that executes control communications and configuration modules 2032A-2032R) is generally responsible for participating in controlling how data (e.g., packets) is routed (e.g., the next hop of the data and the output physical NI of the data) and is responsible for storing the routing information in the forwarding tables 2034A-2034R, and the ND forwarding plane 2026 is responsible for receiving the data on the physical NI 2016 and forwarding the data to the appropriate physical NI in the physical NI 2016 based on the forwarding tables 2034A-2034R.

[0135] Figure 20B An example manner for implementing a dedicated network device 2002 according to some embodiments of the present invention is shown. Figure 20B A dedicated network device is shown including a card 2038 (typically hot-swappable). Although in some embodiments, the cards 2038 are of two types (one or more that function as the ND forwarding plane 2026 (sometimes referred to as line cards), and one or more that function to implement the ND control plane 2024 (sometimes referred to as control cards)), alternative embodiments may combine functionality onto a single card and / or include additional card types (e.g., an additional type of card may be referred to as a service card, resource card, or multi-application card). The service cards may provide specialized processing (e.g., layer 4 to layer 7 services (e.g., firewall, Internet Protocol Security (IPsec), Secure Sockets Layer (SSL) / Transport Layer Security (TLS), intrusion detection system (IDS), peer-to-peer (P2P), voice over IP (VoIP) session border controller, mobile wireless gateway (Gateway General Packet Radio Service (GPRS) Support Node (GGSN), Evolved Packet Core (EPC) gateway)). As an example, a service card may be used to terminate an IPsec tunnel and perform the accompanying authentication and encryption algorithms. The cards are coupled together by one or more interconnect mechanisms, shown as a backplane 2036 (e.g., a first full mesh coupling line cards and a second full mesh coupling all cards).

[0136] return Figure 20A, a general network device 2004 includes hardware 2040, which includes a set of one or more processors 2042 (which are often COTS processors) and a physical NI 2046, and a non-transitory machine-readable storage medium 2048 having stored therein software 2050. During operation, the processor 2042 executes the software 2050 to instantiate one or more sets of one or more applications 2064A-2064R. Although one embodiment does not implement virtualization, alternative embodiments may use different forms of virtualization. For example, in one such alternative embodiment, the virtualization layer 2054 represents the kernel of an operating system (or a shim executing on top of a base operating system) that enables the creation of multiple instances 2062A-2062R, called software containers, each of which can be used to execute one (or more) of the application sets 2064A-2064R; wherein the multiple software containers (also known as virtualization engines, virtual private servers, or jails) are user spaces (typically virtual memory spaces) that are separate from each other and from the kernel space in which the operating system is running; and wherein the application set running in a given user space cannot access the memory of other processes unless explicitly allowed. In another such alternative embodiment, the virtualization layer 2054 represents a hypervisor (sometimes referred to as a virtual machine monitor (VMM)) or a supervisory program that executes on top of a host operating system, and each of the set of applications 2064A-2064R runs on top of a guest operating system within an instance 2062A-2062R, which is called a virtual machine running on top of the hypervisor (in some cases, it can be considered a form of tightly isolated software container) - the guest operating system and applications may not be aware that they are running on a virtual machine instead of a "bare metal" host electronic device, or through paravirtualization, the operating system and / or applications may be aware that virtualization exists for optimization purposes. In other alternative embodiments, one, some or all of the applications are implemented as a monolithic kernel, which can be generated by compiling directly with the application only a limited set of libraries that provide specific OS services required by the application (e.g., from a library operating system (LibOS), including drivers / libraries of OS services). Since a single kernel can be implemented to run directly on hardware 2040, directly on a hypervisor (in which case the single kernel is sometimes described as running within a LibOS virtual machine), or in a software container, an embodiment can be implemented entirely by a single kernel running directly on a hypervisor represented by virtualization layer 2054, a single kernel running within a software container represented by instances 2062A-2062R, or a combination of a single kernel and the above techniques (e.g., a single kernel and virtual machines both running directly on top of a hypervisor, a single kernel and a collection of applications running within different software containers). Note that networking software 2050 includes PCI planner 2055, the operation of which is discussed herein with respect to network device 2002.

[0137] The instantiation and virtualization (if implemented) of one or more sets of one or more applications 2064A-2064R are collectively referred to as software instances 2052. Each set of applications 2064A-2064R, the corresponding virtualization construct (e.g., instances 2062A-2062R) (if implemented), and the portion of the hardware 2040 on which they execute (whether dedicated to that execution and / or a time slice of temporarily shared hardware) form a separate virtual network element 2060A-2060R.

[0138] The virtual network elements 2060A-2060R perform similar functions as the virtual network elements 2030A-2030R—for example, similar to controlling communication and configuration module 2032A and forwarding table 2034A (this virtualization of hardware 2040 is sometimes referred to as network function virtualization (NFV)). Thus, NFV can be used to unify many types of network equipment onto industry-standard high-capacity server hardware, physical switches, and physical storage devices, which can be located in data centers, NDs, and customer premises equipment (CPE). Although embodiments of the present invention are illustrated as each instance 2062A-2062R corresponding to one VNE 2060A-2060R, alternative embodiments may implement this correspondence at a finer level of granularity (e.g., line card virtual machines virtualizing line cards, control card virtual machines virtualizing control cards, etc.); it should be understood that the techniques described herein with reference to the correspondence of instances 2062A-2062R to VNEs are equally applicable to embodiments using such finer levels of granularity and / or a single kernel.

[0139] In some embodiments, the virtualization layer 2054 includes a virtual switch that provides forwarding services similar to a physical Ethernet switch. Specifically, the virtual switch forwards traffic between instances 2062A-2062R and NIC 2046, and optionally forwards traffic between instances 2062A-2062R; in addition, the virtual switch can enforce network isolation (e.g., by implementing virtual local area networks (VLANs)) through policies between VNEs 2060A-2060R that are not allowed to communicate with each other.

[0140] Figure 20A A third exemplary ND implementation in is a hybrid network device 2006 that includes a custom ASIC / proprietary OS and a COTS processor / standard OS in a single ND or a single card within an ND. In certain embodiments of such a hybrid network device, a platform VM (i.e., a VM that implements the functionality of a dedicated network device 2002) can provide paravirtualization to the networking hardware present in the hybrid network device 2006.

[0141] Regardless of the above example implementations of ND, when considering a single one of the multiple VNEs implemented by the ND, or in the case where the NV currently implements only a single VNE, the abbreviated term network element (NE) is sometimes used to refer to the VNE. Also in all of the above example implementations, each VNE (e.g., VNEs 2030A-R, VNEs 2060A-R, and those in hybrid network device 2006) receives data on a physical NI (e.g., 2016, 2046) and forwards the data out to an appropriate physical NI in the physical NIs (e.g., 2016, 2046). For example, a VNE implementing an IP router function forwards IP packets based on some IP header information in the IP packets; wherein the IP header information includes a source IP address, a destination IP address, a source port, a destination port (wherein, in this document, "source port" and "destination port" refer to protocol ports, as opposed to the physical ports of the ND), a transport protocol (e.g., User Datagram Protocol (UDP), Transmission Control Protocol (TCP), and a Differentiated Segment Code Point (DSCP) value).

[0142] Figure 20C Various exemplary ways in which VNEs may be coupled according to some embodiments are shown. Figure 20C Shown are VNEs 2070A.1-2070A.P (and optional VNEs 2070A.Q-2070A.R) implemented in the ND 2000A and VNE 2070H.1 in the ND 2000H. Figure 20C , VNEs 2070A.1-2070A.P are separate from one another in the following sense: they can receive packets from outside ND 2000A and forward packets to outside ND 2000A; VNE 2070A.1 is coupled to VNE 2070H.1, and thus they transmit packets between their respective NDs; VNEs 2070A.2-2070A.3 can optionally forward packets between themselves without forwarding packets to outside ND 2000A; and VNE 2070A.P can optionally be the first in a chain of VNEs that includes VNE 2070A.Q and then VNE 2070A.R (this is sometimes referred to as dynamic service chaining, where each VNE in a series of VNEs provides a different service - for example, one or more layer 4-7 network services). Although Figure 20C Various exemplary relationships between VNEs are shown, and alternative embodiments may support other relationships (e.g., more / fewer VNEs, more / fewer dynamic service chains, multiple different dynamic service chains with some common VNEs and some different VNEs).

[0143] Figure 20AThe ND may, for example, form part of the Internet or a private network; and other electronic devices (not shown; such as end-user devices, including workstations, laptops, netbooks, tablets, handheld computers, mobile phones, smartphones, phablets, multimedia phones, Voice over Internet Protocol (VoIP) phones, terminals, portable media players, GPS units, wearable devices, gaming systems, set-top boxes, Internet-enabled home appliances) may be coupled to the network (directly or through another network such as an access network) to communicate with each other (directly or through a server) and / or access content and / or services over the network (e.g., the Internet or a virtual private network (VPN) overlaid (e.g., tunneled) on the Internet). Such content and / or services are typically provided by one or more servers (not shown) belonging to a service / content provider or one or more end-user devices (not shown) participating in a peer-to-peer (P2P) service, and may include, for example, public web pages (e.g., free content, store front pages, search services), private web pages (e.g., providing username / password access to email services), and / or VPN-based corporate networks. For example, an end-user device may be coupled (e.g., via a customer premises device coupled (wirelessly or wired) to an access network) to an edge ND, which is coupled (e.g., via one or more core NDs) to other edge NDs, which are coupled to electronic devices acting as servers. However, with compute and storage virtualization, as Figure 20A One or more electronic devices operating in the ND may also provide one or more such servers (for example, in the case of the general-purpose network device 2004, one or more of the software instances 2062A-2062R may operate as servers; this would also be true for the hybrid network device 2006; in the case of the dedicated network device 2002, one or more such servers may also run on a virtual layer executed by the processor 2012); in this case, the server is said to be co-located with the VNE of the ND.

[0144] A virtual network is a physical network (e.g., Figure 20A A virtual network can be implemented as an overlay network (sometimes referred to as a network virtualization overlay) that provides network services (e.g., Layer 2 (L2, data link layer) and / or Layer 3 (L3, network layer) services) on an underlay network (e.g., an L3 network such as an Internet Protocol (IP) network that uses tunnels (e.g., Generic Routing Encapsulation (GRE), Layer 2 Tunneling Protocol (L2TP), IPSec) to create an overlay network).

[0145] The Network Virtual Edge (NVE) is located at the edge of the underlying network and participates in implementing network virtualization. The network-facing side of the NVE uses the underlying network to tunnel frames to and from other NVEs. The external-facing side of the NVE sends data to and receives data from systems outside the network. A virtual network instance (VNI) is a specific instance of a virtual network on the NVE (e.g., an NE / VNE on a ND, a portion of an NE / VNE on an ND that is divided into multiple VNEs through simulation in the ND). One or more VNIs can be instantiated on the NVE (e.g., as different VNEs on the ND). A virtual access point (VAP) is a logical connection point on the NVE used to connect external systems to a virtual network. A VAP can be a physical or virtual port identified by a logical interface identifier (e.g., a VLAN ID).

[0146] Examples of network services include: 1) Ethernet LAN emulation service (similar to Internet Engineering Task Force (IETF) Multiprotocol Label Switching (MPLS) Ethernet-based multipoint service or Ethernet VPN (EVPN) service), wherein external systems are interconnected across the network through a LAN environment based on the underlying network (e.g., NVE provides separate L2 VNIs (virtual switching instances) for different such virtual networks, and provides L3 (e.g., IP / MPLS) tunneling encapsulation across the underlying network); and 2) virtualized IP forwarding service (similar to IETF IP VPN (e.g., Border Gateway Protocol (BGP) / MPLS IPVPN) in terms of service definition), wherein external systems are interconnected across the network through an L3 environment based on the underlying network (e.g., NVE provides separate L3 VNIs (forwarding and routing instances) for different such virtual networks, and provides L3 (e.g., IP / MPLS) tunneling encapsulation across the underlying network). Network services may also include quality of service capabilities (e.g., traffic classification marking, traffic conditioning, and scheduling), security capabilities (e.g., filters to protect client terminals from attacks originating from the network to avoid flawed routing announcements), and management capabilities (e.g., full detection and handling).

[0147] Figure 20D shows some embodiments of the present invention. Figure 20A A network with a single network element on each ND is presented, and in this intuitive scheme, a traditional distributed scheme (commonly used by traditional routers) is compared with a centralized scheme for maintaining reachability and forwarding information (also known as network control). Specifically, Figure 20D Shown with Figure 20A The ND2000A-2000H have the same connectivity as the network elements (NE) 2070A-2070H.

[0148] Figure 20D The distributed scheme 2072 is shown to distribute the responsibility for generating reachability and forwarding information across the NEs 2070A-2070H; in other words, the process of neighbor discovery and topology discovery is distributed.

[0149] For example, in the case of a dedicated network device 2002, the control communication and configuration modules 2032A-2032R of the ND control plane 2024 typically include reachability and forwarding information modules to implement one or more routing protocols (e.g., exterior gateway protocols (e.g., Border Gateway Protocol (BGP), interior gateway protocols (IGP) (e.g., Open Shortest Path First (OSPF), Intermediate System to Intermediate System (IS-IS), Routing Information Protocol (RIP)), Label Distribution Protocol (LDP), Resource Reservation Protocol (RSVP) (including RSVP-Traffic Engineering (TE): an extension of RSVP for LSP tunneling, and Generalized Multiprotocol Label Switching (GMPLS) signaling RSVP-TE)), which communicate with other NEs to exchange routes and then select those routes based on one or more routing metrics. Thus, the NE 2070A-2070H (e.g., processor 2012 executing control communication and configuration modules 2032A-2032R) performs its responsibilities for participating in controlling how data (e.g., packets) are routed (e.g., the next hop for the data and the output physical NI for the data) by distributing the reachability within the network and calculating its respective forwarding information. Routes and neighbor relationships are stored in one or more routing structures (e.g., a routing information base (RIB), a label information base (LIB), one or more neighbor relationship structures) on the ND control plane 2024. The ND control plane 2024 uses information based on the routing structures (e.g., neighbor relationships and routing information) to determine the reachability within the network and calculate its respective forwarding information. Programming the ND forwarding plane 2026. For example, the ND control plane 2024 programs neighbor relationships and routing information into one or more forwarding tables 2034A-2034R (e.g., a forwarding information base (FIB), a label forwarding information base (LFIB), and one or more neighbor relationship structures) on the ND forwarding plane 2026. For Layer 2 forwarding, the ND may store one or more bridging tables that are used to forward data based on the Layer 2 information in the data. Although the above example uses a dedicated network device 2002, the same distributed scheme 2072 can be implemented on a general-purpose network device 2004 and a hybrid network device 2006.

[0150] Figure 20DA centralized approach 2074 (also known as software-defined networking (SDN)) is shown that decouples the systems that make decisions about where to send traffic from the underlying systems that forward the traffic to the selected destination. The illustrated centralized approach 2074 has the responsibility for generating reachability and forwarding information in a centralized control plane 2076 (sometimes referred to as an SDN control module, controller, network controller, OpenFlow controller, SDN controller, control plane node, network virtualization mechanism, or management control entity), thereby centralizing the neighbor discovery and topology discovery processes. The centralized control plane 2076 has a southbound interface 2082 to the data plane 2080 (sometimes referred to as the infrastructure layer, network forwarding plane, or forwarding plane (which should not be confused with the ND forwarding plane)), which includes NEs 2070A-2070H (sometimes referred to as switches, forwarding elements, data plane elements, or nodes). The centralized control plane 2076 includes a network controller 2078, which includes a centralized reachability and forwarding information module 2079 that determines reachability within the network and distributes forwarding information to the NEs 2070A-2070H of the data plane 2080 via a southbound interface 2082 (which may use the OpenFlow protocol). Thus, network intelligence is centralized in the centralized control plane 2076, which typically executes on an electronic device separate from the ND. In one embodiment, the centralized reachability and forwarding information module 2079 includes the PCI planner 2055, the operation of which is discussed herein with respect to the network device 2002. In other words, the network controller 2078 may be an electronic device that performs PCI planning for all or a portion of the network.

[0151] For example, in the case where a dedicated network device 2002 is used in the data plane 2080, each control communication and configuration module 2032A-2032R of the ND control plane 2024 typically includes a VNE-side control agent that provides a southbound interface 2082. In this case, the ND control plane 2024 (the processor 2012 executing the control communication and configuration modules 2032A-2032R) performs its responsibilities for participating in controlling how data (e.g., packets) is routed (e.g., the next hop for the data and the output physical NI for the data) via the control agent communicating with the centralized control plane 2076 to receive forwarding information (and in some cases reachability information) from the centralized reachability and forwarding information module 2079 (it should be understood that in some embodiments of the present invention, in addition to communicating with the centralized control plane 2076, the control communication and configuration modules 2032A-2032R may also play a role in determining reachability and calculating forwarding information—although not as much as in the case of a distributed approach; such embodiments are generally considered to fall within the centralized approach 2074, but may also be considered a hybrid approach).

[0152] Although the above example uses a dedicated network device 2002, the same centralized scheme 2074 can be implemented using general-purpose network devices 2004 and hybrid network devices 2006 (e.g., each VNE 2060A-2060R performs its responsibility for controlling how data (e.g., packets) is routed (e.g., the next hop for the data and the output physical NI for the data) by communicating with the centralized control plane 2076 to receive forwarding information (and in some cases, reachability information) from the centralized reachability and forwarding information module 2079; it should be understood that in some embodiments of the present invention, in addition to communicating with the centralized control plane 2076, the VNE 2060A-2060R may also play a role in determining reachability and / or calculating forwarding information - although not as much as in the case of a distributed scheme). In fact, the use of SDN technology can enhance the NFV technology typically used in general-purpose network device 2004 or hybrid network device 2006 implementations because NFV can support SDN by providing an infrastructure on which SDN software can run, and because both NFV and SDN are intended to utilize commodity server hardware and physical switches.

[0153] Figure 20D Also shown is a centralized control plane 2076 having a northbound interface 2084 to an application layer 2086, where applications 2088 reside. The centralized control plane 2076 has the ability to form a virtual network 2092 (sometimes referred to as a logical forwarding plane, network services, or overlay network (with the NEs 2070A-2070H of the data plane 2080 being the underlying network)) for the applications 2088. Thus, the centralized control plane 2076 maintains a global view of all NDs and configured NEs / VNEs, and it efficiently maps virtual networks to the underlying NDs (including maintaining these mappings when the physical network changes due to hardware (NDs, links, or ND components) failures, additions, or removals).

[0154] although Figure 20DA distributed approach 2072 is shown that is different from the centralized approach 2074. In certain embodiments of the present invention, the work of network control may be distributed in different ways or the two may be combined. For example: 1) an embodiment may generally use a centralized approach (SDN) 2074, but with certain functions delegated to the NE (e.g., a distributed approach may be used to implement one or more of fault monitoring, performance monitoring, protection switching, and primitives for neighbor and / or topology discovery); or 2) an embodiment of the present invention may perform neighbor discovery and topology discovery via both a centralized control plane and a distributed protocol, and compare the results to raise anomalies where they disagree. Such embodiments are generally considered to fall within the centralized approach 2074, but may also be considered a hybrid approach).

[0155] although Figure 20D The simple case where each ND 2000A-2000H implements a single NE 2070A-2070H is shown. It should be understood that: Figure 20D The described network control scheme is equally applicable to networks in which one or more NDs 2000A-2000H implement multiple VNEs (e.g., VNEs 2030A-2030R, VNEs 2060A-2060R, or those in hybrid network device 2006). Alternatively or additionally, the network controller 2078 can also emulate the implementation of multiple VNEs in a single ND. Specifically, instead of (or in addition to) implementing multiple VNEs in a single ND, the network controller 2078 can (also) present the implementation of a VNE / NE in a single ND as multiple VNEs in a virtual network 2092 (all in the same virtual network 2092, each in a different virtual network 2092, or some combination thereof). For example, the network controller 2078 can enable the ND to implement a single VNE (NE) in the underlying network, and then logically partition the resources of the NE within the centralized control plane 2076 to present different VNEs in the virtual network 2092 (wherein these different VNEs in the underlying network share the resources implemented by the single VNE / NE on the ND in the underlying network).

[0156] on the other hand, Figure 20E and Figure 20F Exemplary abstractions of NEs and VNEs are shown, respectively, which the network controller 2078 can present as part of different virtual networks 2092. Figure 20E The following simple case according to some embodiments of the present invention is shown: each of the NDs 2000A-2000H implements a single NE of the NEs 2070A-2070H (see Figure 20D), and the centralized control plane 2076 abstracts multiple NEs (NE 2070A-2070C and 2070G-2070H) in different NDs into (represented by) Figure 20D A single NE 2070I in one of the virtual networks 2092. Figure 20E It is shown that in this virtual network, NE 2070I is coupled to NE 2070D and 2070F, which are still coupled to NE 2070E.

[0157] Figure 20F The following scenario is shown according to some embodiments of the present invention: multiple VNEs (VNE 2070A.1 and VNE 2070H.1) are implemented on different NDs (ND 2000A and ND 2000H) and the multiple VNEs are coupled to each other, and the centralized control plane 2076 abstracts these multiple VNEs so that they appear as Figure 20D A single VNE 2070T in one of the virtual networks 2092. Thus, the abstraction of a NE or VNE can span multiple NDs.

[0158] Although some embodiments of the present invention implement the centralized control plane 2076 as a single entity (e.g., a single instance of software running on a single electronic device), alternative embodiments may distribute functionality across multiple entities (e.g., multiple instances of software running on different electronic devices) for redundancy and / or scalability purposes.

[0159] Similar to the network device implementation, the electronic devices running on the centralized control plane 2076, and thereby the network controller 2078 including the centralized reachability and forwarding information module 2079, can be implemented in various ways (e.g., dedicated devices, general-purpose (e.g., COTS) devices, or hybrid devices). These electronic devices will similarly include a processor, a set of one or more physical NICs, and a non-transitory machine-readable storage medium having the centralized control plane software stored thereon. For example, Figure 21 A general purpose control plane device 2104 is shown including hardware 2140 comprising a collection of one or more processors 2142 (which are often COTS processors) and a physical NI 2146, and a non-transitory machine-readable storage medium 2148 having stored therein centralized control plane (CCP) software 2150. In one embodiment, the CCP software 2150 includes a PCI planner 2055, the operation of which is discussed herein with respect to the network device 2102.

[0160] In embodiments using computing virtualization, the processor 2142 typically executes software to instantiate a virtualization layer 2154 (e.g., in one embodiment, the virtualization layer 2154 represents the kernel of an operating system (or a logical layer executing on a base operating system), which allows the creation of multiple instances 2162A-2162R called software containers (representing separate user spaces and also referred to as virtualization engines, virtual private servers, or virtual jails), each of which can be used to execute a collection of one or more applications; in another embodiment, the virtualization layer 2154 represents a hypervisor (sometimes referred to as a virtual machine monitor (VMM)) or a hypervisor that executes on top of a host operating system, and applications are run on virtual machines called jails that are run by the hypervisor). In another embodiment, the application is implemented as a monolithic kernel, which can be generated by directly compiling only a limited set of libraries that provide specific OS services required by the application (e.g., from a library operating system (LibOS), including drivers / libraries of OS services), with the application, and the monolithic kernel can run directly on the hardware 2140, directly on the hypervisor represented by the virtualization layer 2154 (in which case the monolithic kernel is sometimes described as running in a LibOS virtual machine), or in a software container represented by one of the instances 2162A-2162R. Similarly, in an embodiment using compute virtualization, during operation, an instance of the CCP software 2150 (shown as CCP instance 2176A) executes on top of the virtualization layer 2154 (e.g., within instance 2162A). In embodiments that do not use compute virtualization, CCP instance 2176A executes on a "bare metal" general purpose control plane device 2104, either as a single kernel or on a host operating system. The instantiation of CCP instance 2176A, along with virtualization layer 2154 and instances 2162A-2162R (if implemented), is collectively referred to as software instance 2152.

[0161] In some embodiments, the CCP instance 2176A includes a network controller instance 2178. The network controller instance 2178 includes a centralized reachability and forwarding information module instance 2179 (a middleware layer that provides the operating system with the context of the network controller 2078 and communicates with various NEs), and a CCP application layer 2180 (sometimes referred to as the application layer) above the middleware layer (providing the intelligence required for various network operations, such as protocols, network context awareness, and user interfaces). At a more abstract level, the CCP application layer 2180 in the centralized control plane 2076 operates using a virtual network view (a logical view of the network), and the middleware layer provides conversion from the virtual network to the physical view. In one embodiment, the PCI planner 2055 can be instantiated as the PCI planner instance 2145 in the CCP application layer 2180 and other instances in the corresponding CCP application layers of other software containers.

[0162] The centralized control plane 2076 sends relevant messages to the data plane 2080 based on the CCP application layer 2180 calculation and middleware layer mapping for each flow. A flow can be defined as a set of packets with headers that match a given bit pattern; in this sense, traditional IP forwarding is also flow-based forwarding, where a flow is defined by, for example, the destination IP address; however, in other implementations, a given bit pattern for flow definition may include more fields in the packet header (e.g., 10 or more). Different NDs / NEs / VNEs of the data plane 2080 may receive different messages and, therefore, different forwarding information. The data plane 2080 processes these messages and programs the appropriate flow information and corresponding actions into the forwarding table (sometimes referred to as a flow table) of the appropriate NE / VNE. The NE / VNE then maps the incoming packet to the flow represented in the forwarding table and forwards the packet based on the match in the forwarding table.

[0163] Standards such as OpenFlow define protocols for messages and models for processing packets. The model for processing packets includes: header parsing, packet classification, and making forwarding decisions. Header parsing describes how to interpret packets based on a known set of protocols. Some protocol fields are used to build matching structures (or keys) that will be used in packet classification (for example, the first key field can be the source media access control (MAC) address, and the second key field can be the destination MAC address).

[0164] Packet classification involves performing a search in a memory to classify packets by determining which entry in the forwarding table (also referred to as a forwarding table entry or flow entry) best matches the packet based on the matching structure or key of the forwarding table entry. It is possible that many flows represented in the forwarding table entry correspond to / match a packet; in this case, the system is typically configured to determine a forwarding table entry (e.g., select the first forwarding table entry that matches) from many forwarding table entries according to a definition scheme. The forwarding table entry includes a specific set of matching criteria (a value set or wildcard, or an indication of what part of the packet should be compared with a specific value / multiple specific values / wildcards, as defined by matching capability - for a specific field in the packet header or for some other packet content) and a set of one or more actions to be taken for the data plane when receiving a matching packet. For example, an action can be: for a packet using a specific port, a header is pushed onto the packet, the packet is flooded, or the packet is simply discarded. Thus, the forwarding table entry for an IPv4 / IPv6 packet with a specific Transmission Control Protocol (TCP) destination port can include an action that specifies that these packets should be discarded.

[0165] Based on the forwarding table entries identified during packet classification, making forwarding decisions and performing actions occurs by executing the set of actions identified in the matching forwarding table entry for the packet.

[0166] However, when an unknown packet (e.g., a "missed packet" or "match miss" as used in OpenFlow parlance) arrives at the data plane 2080, the packet (or a subset of the packet header and content) is typically forwarded to the centralized control plane 2076. The centralized control plane 2076 then programs a forwarding table entry into the data plane 2080 to accommodate packets belonging to the flow of the unknown packet. Once the centralized control plane 2076 programs a particular forwarding table entry into the data plane 2080, the next packet with matching credentials will match that forwarding table entry and take the set of actions associated with the matched entry.

[0167] A network interface (NI) can be physical or virtual; and in the context of IP, an interface address is an IP address assigned to a NI, whether physical or virtual. A virtual NI can be associated with a physical NI, associated with another virtual interface, or independent (e.g., a loopback interface, a Point-to-Point Protocol interface). NIs (physical or virtual) can be numbered (NIs with IP addresses) or unnumbered (NIs without IP addresses). A loopback interface (and its loopback address) is a specific type of virtual NI (and IP address) often used for management purposes for NEs / VNEs (physical or virtual); such an IP address is referred to as a node loopback address. The IP address assigned to an NI of an ND is referred to as the IP address of the ND; at a more granular level, the IP address assigned to an NI assigned to an NE / VNE implemented on an ND can be referred to as the IP address of the NE / VNE.

[0168] The routing system's selection of a next hop for a given destination can resolve to one path (i.e., the routing protocol can generate one next hop on the shortest path); however, if the routing system determines that there are multiple feasible next hops (i.e., the forwarding solution generated by the routing protocol provides more than one next hop associated with the shortest path - multiple equal-cost next hops), certain additional criteria are used - for example, in connectionless networks, equal-cost multipath (ECMP) (also known as equal-cost multipathing, multipath forwarding, and IP multipath) can be used (for example, typical implementations use specific header fields as criteria to ensure that packets of a particular packet flow are always forwarded on the same next hop to preserve packet flow ordering). For the purposes of multipath forwarding, a packet flow is defined as a set of packets that share an ordering constraint. As an example, a set of packets in a particular TCP transmission sequence needs to arrive in order, otherwise the TCP logic will interpret the out-of-order transmission as congestion and slow the TCP transmission rate.

[0169] A Layer 3 (L3) Link Aggregation (LAG) link is a link that directly connects two NDs that have multiple IP-addressed link paths (each link path is assigned a different IP address), and the load distribution decisions across these different link paths are performed at the ND forwarding plane; in this case, the load distribution decisions are made between the link paths.

[0170] Each VNE (e.g., a virtual router, a virtual bridge (which can function as a virtual switch instance in a virtual private LAN service (VPLS))) is typically independently manageable. For example, in the case of multiple virtual routers, each virtual router can share system resources but be isolated from the other virtual routers with respect to its administrative domain, AAA (authentication, authorization, and accounting) namespace, IP address, and routing database. Multiple VNEs can be employed in an edge ND to provide direct network access and / or different classes of services to subscribers of a service and / or content provider.

[0171] Within some NDs, "interfaces" independent of the physical NI may be configured as part of the VNE to provide higher layer protocols and service information (e.g., layer 3 addressing). In addition to other subscriber configuration requirements, the subscriber record in the AAA server also identifies which context (e.g., which VNE / NE) the corresponding subscriber should be bound to within the ND. As used herein, a binding forms an association between a physical entity (e.g., a physical NI, a channel) or a logical entity (e.g., a circuit such as a subscriber circuit or a logical circuit (a collection of one or more subscriber circuits)) and a context interface on which a network protocol (e.g., a routing protocol, a bridging protocol) is configured for the context. Subscriber data flows on the physical entity when some higher layer protocol interfaces are configured and associated with the physical entity.

[0172] Alternative Embodiments

[0173] Although it has been about Figures 8 to 21 The embodiments of the present invention are described, but the embodiments of the present invention are not limited to Figures 8 to 21 The embodiments described are intended to be limiting and alternative embodiments may be implemented.

[0174] Although the present invention has been described in terms of several embodiments, those skilled in the art will recognize that the present invention is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is therefore to be regarded as illustrative rather than restrictive.

Claims

1. A method for physical layer sub-cell identity allocation to select a sub-cell identity vector for a network device in a wireless network, the method comprising: selecting (1804) a plurality of sub-cell identification vector candidates for the network device from a set of possible sub-cell identification vector candidates, wherein the network device has a plurality of sectors, each sector to be assigned a sub-cell identification within a sub-cell identification vector, and wherein the selecting removes one or more possible sub-cell identification vector candidates that include the same sub-cell identification for two or more adjacent sectors of the network device; determining (1806) a plurality of collision measurements for each sub-cell identification vector candidate of the plurality of sub-cell identification vector candidates, each collision measurement being for a metric measuring sub-cell identification collisions of the plurality of sectors with one or more neighboring cells of the network device in the wireless network, each of the one or more neighboring cells belonging to another network device; deriving (1808) a single value from the plurality of conflict measurements for each of the plurality of sub-cell identification vector candidates; and selecting (1810) a sub-cell identification vector for the network device from the plurality of sub-cell identification vector candidates based on the single value; The plurality of conflict measurements include one or more of the following metrics: facing factor measurements for facing factors between the plurality of sectors and the one or more neighboring cells, wherein the facing factors reflect relative positions between the sectors and the neighboring cells; a size measurement of one or more overlapping areas between the plurality of sectors and the one or more neighboring cells; route length measurements for route lengths in the one or more overlapping areas between the plurality of sectors and the one or more neighboring cells; and A size measurement of building areas in the one or more overlapping regions between the plurality of sectors and the one or more neighboring cells.

2. The method according to claim 1, further comprising: Based on the plurality of sectors, a set of possible sub-cell identification vector candidates is determined (1802).

3. The method according to claim 1 or 2, wherein: The plurality of conflicting measurements include one or more of the following metrics: a number of conflicts between the plurality of sectors and the one or more neighboring cells; said number of conflicting distance measurements; and the number of conflicting relative bearing measurements.

4. The method according to claim 1 or 2, wherein: Deriving the single value from the plurality of conflicting measurements for each of the plurality of sub-cell identification vector candidates comprises: normalizing each of the plurality of collision measurements to be within the same range of values; and The plurality of conflicting measurements are combined into the single value after the normalization.

5. The method according to claim 4, wherein The combining of the plurality of conflicting measurements uses different weights for at least a subset of the plurality of conflicting measurements.

6. The method according to claim 4, wherein: The sub-cell identification vector is mapped to a minimum value or a maximum value among the derived single values, each single value being for one of the plurality of sub-cell identification vector candidates.

7. The method according to claim 1 or 2, wherein: Each sub-cell identifier is an integer, with a value of 0, 1, or 2.

8. An electronic device (2002, 2004, 2104) for physical layer sub-cell identity allocation to select a sub-cell identity vector for a network device in a wireless network, comprising: A processor (2012, 2042, 2142) and a non-transitory computer-readable storage medium (2018, 2048, 2148) providing instructions that, when executed by the processor, cause the electronic device to: selecting (1804) a plurality of sub-cell identification vector candidates for the network device from a set of possible sub-cell identification vector candidates, wherein the network device has a plurality of sectors, each sector to be assigned a sub-cell identification within a sub-cell identification vector, and wherein the selecting removes one or more possible sub-cell identification vector candidates that include the same sub-cell identification for two or more adjacent sectors of the network device; determining (1806) a plurality of collision measurements for each sub-cell identification vector candidate of the plurality of sub-cell identification vector candidates, each collision measurement being for a metric measuring sub-cell identification collisions of the plurality of sectors with one or more neighboring cells of the network device in the wireless network, each of the one or more neighboring cells belonging to another network device; deriving (1808) a single value from the plurality of conflict measurements for each of the plurality of sub-cell identification vector candidates; and selecting (1810) a sub-cell identification vector for the network device from the plurality of sub-cell identification vector candidates based on the single value; The plurality of conflict measurements include one or more of the following metrics: facing factor measurements for facing factors between the plurality of sectors and the one or more neighboring cells, wherein the facing factors reflect relative positions between the sectors and the neighboring cells; a size measurement of one or more overlapping areas between the plurality of sectors and the one or more neighboring cells; route length measurements for route lengths in the one or more overlapping areas between the plurality of sectors and the one or more neighboring cells; and A size measurement of building areas in the one or more overlapping regions between the plurality of sectors and the one or more neighboring cells.

9. The electronic device according to claim 8, further performing: Based on the plurality of sectors, a set of possible sub-cell identification vector candidates is determined (1802).

10. The electronic device according to claim 8 or 9, wherein: The plurality of conflicting measurements include one or more of the following: a number of conflicts between the plurality of sectors and the one or more neighboring cells; said number of conflicting distance measurements; and the number of conflicting relative bearing measurements.

11. The electronic device according to claim 8 or 9, wherein: Deriving the single value from the plurality of conflicting measurements for each of the plurality of sub-cell identification vector candidates comprises: normalizing each of the plurality of collision measurements to be within the same range of values; and The plurality of conflicting measurements are combined into the single value after the normalization.

12. The electronic device according to claim 11, wherein The combining of the plurality of conflicting measurements uses different weights for at least a subset of the plurality of conflicting measurements.

13. The electronic device according to claim 11, wherein The sub-cell identification vector is mapped to a minimum value or a maximum value among the derived single values, each single value being for one of the plurality of sub-cell identification vector candidates.

14. The electronic device according to claim 8 or 9, wherein: Each sub-cell identifier is an integer, with a value of 0, 1, or 2.

15. A non-transitory computer-readable storage medium (2018, 2048, 2148) providing instructions that, when executed by a processor, cause an electronic device to: A plurality of sub-cell identification vector candidates for a network device in a wireless network are selected (1804) from a set of possible sub-cell identification vector candidates, wherein The network device has a plurality of sectors, each sector to be assigned a sub-cell identifier within a sub-cell identifier vector, and wherein the selecting removes one or more possible sub-cell identifier vector candidates that include the same sub-cell identifier for two or more adjacent sectors of the network device; determining (1806) a plurality of collision measurements for each sub-cell identification vector candidate of the plurality of sub-cell identification vector candidates, each collision measurement being for a metric measuring sub-cell identification collisions of the plurality of sectors with one or more neighboring cells of the network device in the wireless network, each of the one or more neighboring cells belonging to another network device; deriving (1808) a single value from the plurality of conflict measurements for each of the plurality of sub-cell identification vector candidates; and selecting (1810) a sub-cell identification vector for the network device from the plurality of sub-cell identification vector candidates based on the single value; wherein the plurality of conflict measurements include one or more of the following metrics: facing factor measurements for facing factors between the plurality of sectors and the one or more neighboring cells, wherein the facing factors reflect relative positions between the sectors and the neighboring cells; a size measurement of one or more overlapping areas between the plurality of sectors and the one or more neighboring cells; route length measurements for route lengths in the one or more overlapping areas between the plurality of sectors and the one or more neighboring cells; and A size measurement of building areas in the one or more overlapping regions between the plurality of sectors and the one or more neighboring cells.

16. The non-transitory computer-readable storage medium of claim 15, wherein: The plurality of conflicting measurements include one or more of the following metrics: a number of conflicts between the plurality of sectors and the one or more neighboring cells; said number of conflicting distance measurements; and the number of conflicting relative bearing measurements.

17. The non-transitory computer-readable storage medium according to claim 15 or 16, wherein: Deriving the single value from the plurality of conflicting measurements for each of the plurality of sub-cell identification vector candidates comprises: normalizing each of the plurality of collision measurements to be within the same range of values; and The plurality of conflicting measurements are combined into the single value after the normalization.

Images