Dimensioning approach for data networks

Abstract

A network dimensioning algorithm for networks, such as DOCSIS 3.1 networks, is described. The present system and method combines per-profile traffic characteristics, available bandwidth, legacy coexistence, and detail overhead contributions of cyclic prefix, pilots, excluded subcarriers, FEC, and bit loading among other parameters.

Description

BACKGROUND

Cable data networks have evolved throughout the years to the current fairly complex system that DOCSIS 3.1 represents. The DOCSIS 3.1 multicarrier system has a variety of sources of overhead that have to be taken into account when estimating capacity. The introduction of profiles has introduced a new layer of complexity as each profile, depending on its traffic characteristics and the channel conditions of its related end-devices, will have its own efficiency estimate. The determination of resources consumed allows cable operators to determine how to best assign spectrum, network device ports and how to configure the network devices to meet desired performance levels for their subscribers. It is also a tool for operators to determine the appropriate time to upgrade and purchase equipment as the demand for capacity continues to grow.

SUMMARY OF THE INVENTION

A network dimensioning algorithm for networks, such as that included in DOCSIS 3.1, is described. The algorithm combines per profile traffic characteristics, available bandwidth, legacy coexistence and detail overhead contributions of cyclic prefix, pilots, excluded subcarriers, FEC and bit loading, among other parameters.

The present dimensioning approach to data network systems and methods may be implemented externally to the cable modem terminal system (CMTS) and the cable modem (CM) for purposes of collecting data therefrom. In addition, the present system and method may also collect data regarding traffic through the CMTS and CM. The collected data is utilized according to the instructions presented here for the calculation of capacity and efficiency, which may then be used to select the appropriate transmission patterns, and thereby the best balance of efficiency and robustness for a given network path.

In an embodiment, in addition to the collection of CMTS configuration parameters that rely on the CMTS's internal algorithms, the present dimensioning system may also externally optimize the CMTS data based on traffic and channel conditions and then communicate the results back to the CMTS. Based at least in part on the results, the upstream algorithm assesses whether greater efficiencies may be gained by utilizing a lower modulation order body minislot and transmitting through the impairment or by skipping over the impairment and beginning the transmission of an edge minislot.

In an example of a downstream embodiment, a similar process to that described above in the upstream embodiments may be used. For example, in the case of a wideband interferer, like LTE ingress, carriers are not automatically excluded. Instead, an ingress level and the OFDM signal level per profile assessment is made to determine the use of FEC and frequency interleaving to overcome, rather than avoid, the wideband interference.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram illustrating one exemplary structure of a profile and overall capacity and efficiency calculator, in an embodiment.

FIG. 2 is a flowchart illustrating one exemplary method for a dimensioning approach for downstream data in a data network, in an embodiment.

FIG. 3 is one example of a Collect PLC information step from the method of FIG. 2, in an embodiment.

FIG. 4 is one example of a Traffic Data step from the method of FIG. 2, in an embodiment.

FIG. 5 is a continuation of the method of FIG. 2, in an embodiment.

FIG. 6 is a flowchart illustrating one exemplary method for a dimensioning approach for upstream data in a data network, in an embodiment.

FIG. 7 is one example of a Data Collect step from the method of FIG. 6, in an embodiment.

FIG. 8 is one example of a Traffic and FEC impact step from the method of FIG. 6, in an embodiment.

FIG. 9 is a graph illustrating a roll-off window and legacy/OFDM separation optimization, in an embodiment.

FIG. 10 shows exemplary upstream Pilot structures in Patterns 1 through 7, each with body minislots and edge minislots, in an embodiment.

FIG. 11 shows exemplary upstream Pilot structures in Patterns 8 through 11, each with body minislots and edge minislots, in an embodiment.

FIG. 12 shows exemplary upstream Pilot structures in Patterns 12 through 14, each with body minislots and edge minislots, in an embodiment.

FIGS. 13-17, which show an exemplary upstream FEC efficiency Calculator, should be viewed together.

FIG. 13 is one exemplary table showing results for an upstream FEC Efficiency Calculator, in an embodiment.

FIG. 14 shows formulas utilized in the table of FIG. 13 for the upstream FEC Efficiency Calculator, in an embodiment.

FIG. 15 is one exemplary table showing results for an upstream FEC Efficiency Calculator, in an embodiment.

FIG. 16 shows formulas utilized in the table of FIG. 15 for the upstream FEC Efficiency Calculator, in an embodiment

FIG. 17 is a graph illustrating an Upstream Efficiency vs. Information size in bytes as determined by the upstream FEC efficiency calculator of FIGS. 13-16, in an embodiment.

FIG. 18 is a graph illustrating an Upstream Efficiency vs. Codeword size in bytes as determined by the upstream FEC efficiency calculator of FIGS. 13-16, in an embodiment.

FIGS. 19-25E, which show an exemplary DOCSIS 3.1 upstream efficiency calculator, are best viewed together.

FIG. 19 shows field data and references used in a DOCSIS 3.1 efficiency calculator, in an embodiment.

FIGS. 20A-25E are aspects of the DOCSIS 3.1 upstream efficiency calculator.

FIGS. 26-30 are best viewed together.

FIG. 26 shows aspects of the DOCSIS 3.1 upstream efficiency calculator of FIGS. 19-25E shown in detail, in an embodiment.

FIGS. 27-30 are aspects of the DOCSIS 3.1 upstream efficiency calculator of FIG. 26 shown in detail.

FIGS. 31-35 are best viewed together.

FIGS. 31-33C are a plurality of upstream use cases showing results of the of applied algorithms, in an embodiment.

FIG. 33D shows a mixing calculator, the formulas of which are shown in FIG. 35, which calculates transmission rates for each of the 4a-6b+ cases for mixing of DOCSIS 3.1 and 3.0 systems at a 5% mixing penalty.

FIG. 34 shows use cases 1, 4a and 4a+ of FIG. 31 with results replaced by formulas that produce those results, in an embodiment.

FIG. 35 shows an aspect of FIG. 33D with results replaced by formulas that produce those results, in an embodiment.

FIGS. 36A-B show downstream use cases, with results (FIG. 36A) and formulas (FIG. 36B) that produce those results.

FIGS. 37A-B show upstream use cases, with results (FIG. 37A) and formulas (FIG. 37B) that produce those results.

FIG. 38 is a portion of a DOCSIS 3.1 downstream efficiency calculator showing results of calculations, in an embodiment.

FIG. 38A shows formulas that produce the results shown in FIG. 38.

FIG. 38B is a portion of a DOCSIS 3.1 downstream efficiency calculator showing results of calculations, in an embodiment.

FIGS. 38C-D and 39 show formulas that produce the results shown in FIG. 38B.

FIGS. 39A-J are best viewed together.

FIGS. 39A-G show aspects of a downstream bit loading, pilots, and exclusions calculator in detail showing formulas and results produced by those formulas.

FIG. 39H is a 4K FFT Diagram at a subcarrier spacing of 50 KHz, in an embodiment.

FIG. 39I is an 8K FFT Diagram at a subcarrier spacing of 25 KHz, in an embodiment.

FIG. 39J is an 8K FFT Diagram at a subcarrier spacing of 25 KHz with alternating pilots, in an embodiment.

DETAILED DESCRIPTION OF THE FIGURES

Cable data networks have evolved throughout the years to their current level of complexity, as described in the DOCSIS 3.1 implementation. This multicarrier data network system has a plurality of overhead sources that must to be taken into account when calculating system capacity. Adding profiles has introduced an extra layer of complexity due to the fact that efficiency estimates are profile dependent. That is, each profile depends on at least data traffic characteristics and end-device channel conditions. A diagram showing some general dependencies that may be taken into account is shown in FIG. 1.

FIG. 1 shows some of the general parametric dependencies for dimensioning a DOCSIS 3.1 network. A more detailed description of the network dimensioning process in the downstream and upstream directions may be calculated by modeling, for example, user traffic characteristics and conditions that exist on network channels. These details are expanded on in the following description and associated figures.

FIG. 1 shows the basic structure of a profile and overall capacity and efficiency calculator 100 in an embodiment. System 100 includes a user population 102, which influences profiles' services and applications 104, profiles' packet size distributions 106, and profiles' channel conditions 108. Profiles' services and applications 104 and packet size distribution 106 influence profiles' traffic signatures 110. Profiles' channel conditions 108 influence profiles' configuration parameters 112. Profiles' traffic signatures 110 and profiles' configuration parameters 112 together are inputs into a capacity estimation function 114, which in turn outputs a per profile overall capacity and efficiency 116.

The user population 102 is a group of data service users that as an aggregate has specific transmission characteristics. The user population sharing specific network configuration parameters, channel conditions and traffic characteristics is used to estimate the network resources it consumes.

The services and applications 104 are defined as follows. A service is defined as a two-way data connection to a subscriber that meets specific levels of performance and is associated to certain traffic characteristics. In this context, an application is a specific purpose program that uses a two-way data connection and is also associated with certain traffic characteristics.

The packet size distribution 106 describes the different packet length statistics in bytes or bits of upstream or downstream transmissions. This distribution provides insight on transport efficiency as the overhead of a shorter packet is different than the overhead of a longer packet.

The channel conditions 108 indicate the noise, distortion and other unwanted signal characteristics occupying the different portions of the channel spectrum. The channel conditions provide the necessary information to decide how to use the channel and transmit the desired information carrying signals.

Traffic signatures 110 describe the transmission characteristics using attributes such as number of packets in transmission, packet duration or length (packet size distribution) and period of time of transmission. Traffic signatures can be defined for individual subscriber transmissions, for transmissions related to specific services or applications or by any selection or grouping of subscribers or traffic.

Configuration parameters 112 indicate the operational settings selected by operators or automatically set by the network equipment.

The capacity estimation function 114 estimates the effective capacity available from the network under the conditions assumed and configurations selected. It is a collection of algorithms that use a diversity of inputs such as configuration parameters and traffic signatures to provide the effective capacity.

FIGS. 2-5 show a downstream network dimensioning method 200 utilized in a data network. The present embodiment is described for use in a DOCSIS 3.1 environment, although it will be understood that the present method may be adapted to other data networks without departing from the scope herein. The methods of FIGS. 2-8 are represented in one embodiment by the graphs, spread sheets, and algorithms shown in FIGS. 9-39J.

Step 202 starts method 200, which then moves to step 204.

In step 204, method 200 identifies the legacy use of spectrum and node capacities to determine the total downstream DOCSIS 3.1 occupied spectrum in nodes. Method 200 then moves to step 206.

In step 206, method 200 determines both the unused spectrum and unusable spectrum within the total occupied spectrum of the data network. Method 200 then moves to step 208.

In step 208, method 200 examines the first (or the next) i-th channel, for example, utilizing a downstream FFT function. Method 200 then moves to step 210.

In step 210, method 200 collects PLC data. Method 200 then moves to step 212 where method 200 collects traffic data. Examples of method steps 210 and 212 are shown in detail in FIGS. 3 and 4, respectively. Method 200 then moves to step 214.

In step 214, method 200 utilizes cyclic prefix data and net symbol period data to determine a time efficiency which may be represented, for example, as a percentage. Method 200 then moves to step 216.

In step 216, method 200 determines the modulated bandwidth of the system and stores the upper bound for a number of subcarriers in, for example, a temporary storage variable “S”. Method 200 then moves to step 218.

In step 218, method 200 utilizes the occupied bandwidth and guard band or encompassed bandwidth to determine an upper and a lower active sub-carrier frequency. Method 200 then moves to decision step 220.

In decision step 220, method 200 determines if the occupied bandwidth and guard band are available. If step 220 determines that the occupied bandwidth and guard band are available, then method 200 moves to step 222, where method 200 utilizes the occupied BW and guard band or the encompassed bandwidth to determine upper and lower active subcarriers frequencies. Method 200 then moves to the first step of FIG. 5. If it is determined in step 220 that no occupied bandwidth and guard bands are available, then step 220 moves to step 224, where method 200 updates the potential subcarriers variable “S” from the encompassed bandwidth. One example of updating the “S” variable is by performing the calculation:[((Upper edge active subcarrier frequency)−(lower edge active subcarrier frequency))/subcarrier spacing]

Method 200 then moves to the first step of FIG. 5.

FIG. 3 shows method 300, which is one example of step 210 of FIG. 2, shown in detail. Step 210 is a step of collecting PHY Link Channel (PLC) information. In step 302, method 300 first determines the subcarrier spacing of the i-th channel from PLC acquisition.

In step 304, method 300 retrieves the cyclic prefix of the i-th channel.

In step 306, method 300 determines the roll-off window of the i-th channel.

In step 308, method 300 determines lower and upper edges of the i-th channel.

In step 310, method 300 determines the number of excluded subcarriers of the i-th channel.

In step 312, method 300 calculates the aggregate bandwidth of the excluded sub-bands for the i-th channel.

In step 314, method 300 determines all of the “M” profile's bit-loading vs. frequency for the i-th channel.

In step 316, method 300 retrieves the number of continuous pilots outside of the PLC in the i-th channel.

In step 318, method 300 adds eight (8) to the outside PLC continuous pilots to generate a total number of continuous pilots.

In step 320, method 300 calculates the number of staggered pilots in the i-th channel.

In step 322, method 300 determines the number of PLC subcarriers. The number of PLC subcarriers is 8 for a subcarrier spacing of 50 KHz and is equal to 16 for a subcarrier spacing of 25 KHz.

Method 300 then moves to step 212 of method 200, FIG. 2.

FIG. 4 shows method 400, which is one example of step 212 of FIG. 2, shown in detail. Step 212 is a step of collecting network traffic data. In step 402, method 400 estimates a profile cycling period for each of the M profiles in i-th channels.

In step 404, method 400 determines the number of users for each of the M profiles in i-th channels.

In step 406, method 400 measures the volumes in bytes for each of the M profiles in i-th channels.

In step 408, method 400 measures the average number of packets for each of the M profiles in i-th channels. Method 400 then moves to step 214 of method 200, FIG. 2.

FIG. 5 is a continuation of the method of FIG. 2, in an embodiment. Steps 222 or 224 of method 300 move to step 502 of FIG. 5, starting method 500.

In step 502, method 500 subtracts the excluded subcarrier to update the “S” variable.

In step 504, method 500 converts the excluded bands to subcarriers and subtracts them from the “S” variable to further update it.

In step 506, method 500 subtracts the continuous pilots that are not in the 6 MHz PLC from the “S” variable to further update it.

In step 508, method 500 subtracts the 8 continuous pilots that are in the 6 MHz PLC from the “S” variable to further update it.

In step 510, method 500 subtracts the staggered/scattered pilots that are in the 6 MHz PLC from the “S” variable to further update it.

In step 512, method 500 determines the number of PLC subcarriers. The number of PLC subcarriers is 8 for a subcarrier spacing of 50 KHz and is equal to 16 for a subcarrier spacing of 25 KHz.

In step 514, method 500 determines the frequency efficiency by dividing the value stored in the “S” variable by the occupied bandwidth, which results in the frequency efficiency which may be represented, for example, as a percentage.

In step 516, method 500 utilizes the profile bit loading to determine the available raw bits for each profile/symbol.

In step 518, method 500 utilizes the Forward Error Correction (FEC), for example, using LDPC & BCH parity bits: 1968 bits, Info bits=14323 bits, Full Length CW bits=16200, to determine a 1st pass at an estimated effective number of bits available for each profile/symbol.

In step 520, method 500 utilizes the number of profiles, volume traffic consumption per profile, and profile cycle duration to determine the average number of symbols per profile cycle to estimate the number of full and shortened codewords for each profile.

In step 522, method 500, based on number of full and shortened codewords, the number of NCP messages, and the number of subcarriers used for NCP Messages, adjust, in a second pass, the estimated effective number of bits available for each profile/symbol after including NCP Overhead.

In step 524, method 500 utilizes the number of effective bits in a profile, multiplied by the time efficiency and divided by the product of occupied bandwidth and symbols/profile, to obtain the effective efficiency in b/s/Hz in each of the profiles.

In step 526, method 500 multiplies the efficiency in each profile by the occupied bandwidth to determine a profile throughput in b/s.

In step 528, method 500 (and 200) determines if method 500 has completed its process of all i-th channels. If method 500 determines it has not completed the process, method 500 moves to step 208 of FIG. 2, otherwise, method 500 ends.

FIGS. 6-8 show an Upstream Network Dimensioning method in a DOCSIS 3.1 embodiment. The method of FIGS. 6-8 is represented in one embodiment by the spread sheets, graphs, and algorithms of FIGS. 9-37B.

Step 602 starts method 600.

In step 604, method 600 determines total upstream DOCSIS 3.1 occupied spectrum in a node based on legacy use of spectrum and node capacities.

In step 606, method 600 determines what portion of the total occupied spectrum is the unused spectrum and the unusable spectrum.

In step 608, method 600 examines the first i-th channel, if this is the first pass through the method; otherwise method 600 examines the next i-th channel. This examination process may be performed, for example, using an upstream FFT Block.

In step 610, method 600 collects data. One exemplary data collection step 610 is shown in detail in FIG. 7 as data collection 700.

In step 612, method 600 utilizes cyclic prefix and net symbol period to determine time efficiency, for example, as a percentage.

In step 614, method 600 determines traffic and FEC impact. One exemplary step 614 is shown in detail in FIG. 8 as data collection 800.

In step 616, method 600 calculates a total # of body and edge minislots in each M profile from the number of grants per profile plus the number of additional edge minislots.

In step 618, method 600 calculates raw bit capacity for each M profile from profile modulation and pilot pattern versus frequency information.

In step 620, method 600 utilizes an effective code rate calculation for each of the profiles to calculate an effective bit capacity after FEC overhead.

In step 622, method 600 determines efficiency in b/s/Hz for each of the M profiles utilizing time efficiency and occupied bandwidth metrics.

In step 624, method 600 determines a profile throughput in bits/sec by multiplying efficiency in each profile by the occupied bandwidth.

In decision step 626, method 600 determines if it is done with all i-th channels. If in step 626 it is determined that method 600 is not done with all i-th channels, it moves to step 610, and otherwise method 600 ends.

FIG. 7 is a method 700, which is one example of step 610 of FIG. 6, shown in detail. In step 702, method 700 determines the subcarrier spacing of an i-th channel.

In step 704, method 700 determines the i-th channel's cyclic prefix.

In step 706, method 700 determines the i-th channel's roll-off window.

In step 708, method 700 determines the i-th channel's lower and upper edges.

In step 710, method 700 calculates potential # of subcarriers and stores it in temp variable “S” based on the retrieved i-th channel's lower and upper edges.

In step 712, method 700 determines minislot parameters, for example, the number of subcarriers, the number of symbols, etc.

In step 714, method 700 calculates the frame duration from “K”, the symbols per frame.

In step 716, method 700 determines a list of intelligent occupancy of upstream spectrum by legacy systems on the network, including center frequency, bandwidth, and expected modulation order.

In step 718, method 700 calculates the minimum gaps required for legacy systems on the network and determines the position and width of excluded sub-bands.

In step 720, method 700 determines the position of excluded subcarriers based on signal-to-noise-ratio (SNR).

In step 722, method 700 determines the guard band(s) required.

In step 724, method 700 determines a list of usable body and gap-related-edge minislots (a.k.a. additional edge minislots) in the i-th channel, from the guard band, excluded subcarriers and excluded sub-bands, such that a minislot generation efficiency is determined.

In step 726, method 700 calculates, for each of the profiles, the effective bit capacity after FEC overhead utilizing the effective code rate.

In step 728, method 700 determines the per profile effective code rate.

Method 700 then moves to step 612 of FIG. 6.

FIG. 8 is a method 800, which is one example of step 614 of FIG. 6, shown in detail. In step 802, method 800 measures a packet size distribution and a volume of traffic in the profiles.

In step 804, method 800 calculates the number of minislots required for each burst size biased on packet size distribution and configuration.

In step 806, method 800 calculates the number of minislots required for each burst size based on the traffic generated in each profile.

In step 808, method 800 calculates the aggregate number of minislots consumed per profile.

In step 810, method 800 calculates the number of simultaneous grants per profile based on traffic characteristics and configuration.

In step 812, method 800 calculates the per packet size effective code rate.

In step 814, method 800 determines the per profile effective code rate.

Method 800 then moves to step 616 of FIG. 6.

FIG. 9 shows one exemplary relationship between legacy and OFDM systems such that they may coexistence on the same network. For example, where the location and modulation order of legacy channels are known or determined, the present system determines an optimization. The separation of legacy and OFDM systems is based on the CNR required by the legacy channel, the amount of adjacent OFDM/OFDMA noise that a particular roll-off window configuration implies, and a separation 902 of the legacy signal to the closest active OFDM/OFDMA subcarrier. The roll-off window requires additional samples that are added to the symbol and have the effect of lowering the energy adjacent to the signal by rolling-off and decreasing the adjacent energy in amplitude at a higher rate than the traditional configured scenario without the additional roll-off samples. This reduces the total amount of energy in the adjacent channel and allows the adjacent portion of the spectrum be occupied by another signal such as a legacy DOC SIS signal. Graph 900 of FIG. 9 shows one example of such a scenario in an up-stream embodiment having a roll-off window and legacy/OFDM separation 902 optimization. In this example, a 64 QAM DOCSIS legacy system that requires 27 dB CNR coexists with an OFDMA system, which operates at a specific power level/bandwidth that is located at a specific frequency separation from the edge of the legacy signal. The time overhead needed in the form of Cyclic Prefix is calculated using an adjacency optimization algorithm plus the delay spread that is obtained from the channel conditions.

FIGS. 10-12 show upstream patterns 1-14 each having specific pilot structures, minislot configurations, etc. as known in the art. The present systems and methods may select the appropriate pattern based on network characteristics.

FIGS. 13 and 14 show the same spread sheet, although FIG. 14 shows the functions that produce the results shown in FIG. 13. Both FIGS. 13 and 14 show the Transmission Payload Range in Bytes, the Codeword types and associated information bits, the transmission payload range in bits, and the Codeword types. FIGS. 13 and 14 also show the codeword bits, parity bits, payload bits, efficiency, payload bytes and parity bytes associated with the long, medium and short Codeword types.

FIGS. 15 and 16 show the same spread sheet, although FIG. 16 shows the functions that produce the results shown in FIG. 15. FIGS. 15 and 16 show the spread sheet which correlates the calculated efficiencies with calculated code word bytes, information bits, information bytes, and codeword type (short, medium and long).

FIG. 17 is a graph of Efficiency vs. Information Size (in bytes) as calculated by the spreadsheet of FIGS. 13-14.

FIG. 18 is a graph of Efficiency vs. Codeword Size (in bytes) as calculated by the spread sheet of FIGS. 15-16.

FIG. 19 shows field data and references used in a DOCSIS 3.1 efficiency calculator. FIGS. 20A-25E are aspects of the DOCSIS 3.1 upstream efficiency calculator.

FIGS. 20A and 20B show the same spread sheet, although FIG. 20B shows the functions that produce the results shown in FIG. 20A.

FIGS. 21A and 21B show the same spread sheet, although FIG. 21B shows the functions that produce the results shown in FIG. 21A.

FIGS. 22A and 22B show the same spread sheet, although FIG. 22B shows the functions that produce the results shown in FIG. 22A.

FIGS. 23A and 23B show the same spread sheet, although FIG. 23B shows the functions that produce the results shown in FIG. 23A.

FIGS. 24A and 24B show the same spread sheet, although FIG. 24B shows the functions that produce the results shown in FIG. 24A.

FIGS. 25 and 25A-25E show the same spread sheet, although FIGS. 25A-E show the functions that produce the results shown in FIG. 25.

FIG. 26 is a spreadsheet for determining DOCSIS 3.1 upstream minislot and exclusions. For sake of clarity, portions of the spread sheet of FIG. 26 are represented in FIGS. 27-30. FIG. 26 shows results produced by the formulas shown in FIGS. 27-30. FIG. 26 also shows excluded subcarrier frequencies 2602.

FIG. 31 shows upstream use cases 1, 4a, and 4a+. The formulas that produce the results for use cases 1, 4a, and 4a+ are shown in FIG. 34. FIG. 32 shows use cases 4b, 4b+, and 5a. FIG. 33A shows uses cases 5a+, 5b and 5b+. FIG. 33B shows use cases 6a and 6a+. FIG. 33C shows use cases 6b, and 6b+. In addition, FIG. 33D also shows a mixing calculator, the formulas of which are shown in FIG. 35, which calculates transmission rates for each of the 4a-6b+ cases for mixing of DOCSIS 3.1 and 3.0 systems at a 5% mixing penalty.

FIGS. 36A and B show 1-3 downstream use cases for ANGA and A-C downstream uses cases for Comcast. FIG. 36B shows the formulas that produce the results presented in FIG. 36A. FIG. 36A also shows a DOCSIS 3.1 uses case B-Poor, with a graphical representation for the time, guardband, Pilot & PLC, NCP, FEC, MAC, and Payload data. For sake of clarity, this graph has been removed from FIG. 36B.

FIGS. 37A and 37B show upstream use cases 1-3 with graphical representation of tie overhead data, legacy, exclusion band, and guardband data, pilot structure overhead, FEC, and PHY payload data. FIGS. 37A and B also show graphical representations of downstream time overhead, guardband, Pilot & PLC, NCP, FEC, excluded subcarriers, and PHY payload for ANGA use cases 1-3.

FIGS. 38 and 38A are portions of a DOCSIS 3.1 downstream efficiency calculator. The formulas that produce the results of FIGS. 38 and 38A are shown in FIGS. 38B-D and 39.

FIGS. 39A-G show aspects of a downstream bit loading, pilots, and exclusions calculator, in an embodiment. FIG. 39B shows the formulas that produce the results of FIG. 39A. FIG. 39D shows the formulas the produce the results shown in FIG. 39C. FIG. 39F shows the formulas that produce the results of FIG. 39E. FIG. 39G shows continuous pilots in PLC data. FIG. 39H shows a 4K FFT Diagram having a subcarrier spacing of 50 KHz, in an embodiment. FIG. 39I shows an 8K FFT Diagram having a subcarrier spacing of 25 KHz, in an embodiment. FIG. 39J shows an 8K FFT Diagram having a subcarrier spacing of 25 KHz with alternating pilots, in an embodiment.

Those skilled in the art will appreciate the use of legacy and DOCSIS 3.1 systems, methods and data in its application to the present dimensioning approach to data networks.

Changes may be made in the above methods and systems without departing from the scope hereof. It should thus be noted that the matter contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method and system, which, as a matter of language, might be said to fall there between.

Claims

1. A method for dimensioning a downstream data network, comprising: determining a total amount of downstream Data Over Cable Service Interface Specification version 3.1 (DOCSIS 3.1) occupied spectrum in a node;determining unused spectrum and unusable spectrum within a total occupied spectrum of the downstream data network;examining an i-th channel;collecting physical link channel (PLC) data;collecting traffic data;determining time efficiency based on cyclic prefix, net symbol period, the collected PLC data and the collected traffic data;determining a modulated bandwidth and storing an upper bound on a number of subcarriers in a temporary variable “S”;determining an upper and a lower active subcarrier frequency based on one or more of an occupied bandwidth, a guardband and an encompassed bandwidth, which is an upper edge active subcarrier frequency minus a lower edge active subcarrier frequency;updating the temporary variable “S” based on the upper and the lower active subcarrier frequencies and further by subtracting (1) excluded subcarriers, (2) excluded bands converted to subcarriers, (3) continuous pilots that are not in 6 MHz PLC, (4) 8 continuous pilots that are in 6 MHz PLC, (5) staggered/scattered pilots in the 6 MHz PLC;determining a number of PLC subcarriers;calculating a frequency efficiency by dividing the updated temporary variable “S” by the occupied bandwidth;determining available raw bits for each profile/symbol using profile bit loading data;determining a number of effective bits available for each profile/symbol based on the available raw bits for each profile/symbol adjusted by forward error correction (FEC) data;determining an average number of symbols per profile cycle to estimate a number of full and shortened codewords for each profile based on a number of profiles, a volume traffic consumption per profile, and a profile cycle duration;adjusting the number of effective bits available for each profile/symbol after including a normal cyclic prefix (NCP) overhead based on the number of full and shortened codewords, a number of NCP messages, and a number of subcarriers used for the NCP messages;obtaining an effective efficiency in bits per second per Hertz (b/s/Hz) in each of the profiles based on the number of effective bits in a profile multiplied by the time efficiency and divided by a product of the occupied bandwidth and symbols/profile; anddetermining a profile throughput in bits per second by multiplying the effective efficiency in each profile by the occupied bandwidth.