Abstract:
A computer-implemented satellite network planning system that enables a user to plan a satellite communications network, using an industry-standard spreadsheet as a platform. The spreadsheet contains embedded equations used to produce a network design that describes components of a physical layer of the planned network (i.e. hub terminals, satellite, and remote terminals), and provides bandwidth allocations and traffic engineering features of the planned network. The spreadsheet includes a user-friendly interface that prompts the user to enter predetermined network parameters but does not display the embedded equations. The result is a user-friendly interface that is familiar enough for most LAN users, designers, and product managers to use and understand the results provided by the network planning system. The use of the industry-standard spreadsheet including the user-friendly interface reduces design time, allows non-technical managers to use the tool, and saves money for the user.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application contains subject matter related to that disclosed in commonly owned U.S. patent application Ser. No. 10/721,496, entitled METHOD, APPARATUS, AND SYSTEM FOR DOWNSTREAM RECOVERY IN A COMMUNICATIONS NETWORK, filed Nov. 26, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates in general to satellite communication networks and in particular to a method, apparatus and system for efficiently designing and planning a shared satellite communications network.  
         [0004]     2. Discussion of the Background  
         [0005]     Geo-synchronous satellite communication networks have existed for decades in various topologies and using various methods for sharing a fixed bandwidth channel between multiple users (Pritchard, Wilbur L., and Joseph A. Scivlli,  Satellite Communication Systems Engineering , Prentice-Hall, 1986, incorporated in its entirety herein by reference). As these networks evolved, shared satellite communications networks have gained popularity for their reach, simplicity, cost-effectiveness, and deploy-ability. An example of a conventional shared satellite communications network is shown in  FIG. 1 .  FIG. 1  illustrates a Hub ( 11 ) communicating via a satellite ( 10 ) with multiple remote terminals ( 12 ) as well as the upstream ( 13 ) and downstream ( 14 ) communication channels. It has been a challenge to deploy a shared network that meets the needs of the end customer, and at the same time meets business goals of a service provider. Most service provider product marketing and analysis personnel are faced with the challenge of not only defining the markets they want to address, but to do so profitably and at the same time meet the customer demand.  
         [0006]     Shared satellite services use various algorithms for determining bandwidth on demand and meeting technology idiosyncrasies involved with a specific network being designed. Most network designers have made designs using rough estimations that are laborious and often not re-usable when designing a different shared satellite network with different parameters, capabilities, or technology idiosyncrasies. Computer implemented tools available in the market place include OPNET, but these conventional tools are very expensive and generally require an expert to implement and analyze the results. These tools are based on a custom operating system that is a challenge for new users to master. The cost (financial cost and labor cost) of using such a tool is too expensive for most service providers, especially small service providers where budgets are strictly enforced and Return On Investment (ROI) times are usually short.  
         [0007]     As recognized by the present inventor, the industry is in need of a computer-based network designing and planning system with an easily understood interface that an end user can use to perform a low-cost analysis and reliably obtain a final network design.  
       SUMMARY OF THE INVENTION  
       [0008]     Accordingly, one object of this invention is to address the above-identified and other problems with conventional systems and methods for designing and planning a shared satellite communications network.  
         [0009]     One aspect of the present invention is that it provides a shared satellite communication network planning system (network planning system) that enables an end user to plan a shared satellite communications network and perform a “what-if” analysis of a planned shared satellite communication network at low cost. The network planning system uses a WINDOWS-based database or spreadsheet (or other industry standard applications that allow for user programmability) as a platform. The use of a database (with programmable calculation features) or spreadsheet as a platform reduces the cost of implementation and overall Information Technology (IT) costs, since most end users already use a database or spreadsheet in their business operations. Furthermore, there is no need for a user to become familiar with an additional operating system, software package, or compiler to use the network planning system.  
         [0010]     Another aspect of the present invention is that it provides a user-friendly interface in which an end user enters certain parameters of the envisioned shared satellite communications network. The user-friendly interface is logical enough for most LAN users, designers, and product managers to use and understand the results provided by the network planning system. The user-friendly interface also functions to conceal the complexities of the background formulas used to produce the final network design that is output by the network planning system.  
         [0011]     The background formulas used to determine the final network design provided by the network planning system consider network parameters such as the following: 
        voice parameters (symmetrical traffic);     data parameters on the upstream (communication from the Remote to Hub);     minimum Committed Information Rate (CIR);     dynamic CIR oversubscription capability;     upstream oversubscription capability;     data parameters on the downstream (communication from the Hub to Remote);     CIR parameters for both upstream and downstream of all sites or subset of sites;     TDMA overhead based on carrier sizes and framelength chosen;     acquisition timeslot window size;     guard band setting for all carriers;     SAR overhead;     link encryption overhead;     symbol rates     frequency hopping or non-frequency hopping designs; and     type of network such as Voice Only, Data Only, Voice Data        
 
         [0027]     The network planning system outputs a final network design (as an example, the design identifies the number of components needed to meet specified performance requirements) that can be implemented by the user. The network planning system provides a final network design including the information for implementing a physical layer (carrier, etc.), an integrated bandwidth allocation budget analysis that is performed for each site, and traffic engineering features.  
         [0028]     In summary, the network planning system provides a user-friendly interface, simple enough for most LAN designers to use, close to accurate results verified with real shared satellite communication networks, an integrated bandwidth allocation budget analysis performed for each site, and integrated traffic engineering features. Further, the network planning system also reduces design time, allows non-technical managers to use the tool, and saves money for the end user.  
         [0029]     One example of a satellite system for which the present invention may be used to design is described in U.S. patent application Ser. No. 10/721,496 filed Nov. 26, 2003. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0030]     A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
         [0031]      FIG. 1  is a diagram of a conventional satellite communication network;  
         [0032]      FIG. 2  is a diagram of a network design provided by the network planning system according to the present invention;  
         [0033]      FIG. 3  is a flow chart of the network planning system;  
         [0034]      FIG. 4  is a screen-dump of a spreadsheet including  8  steps prompting the user to enter the parameters included in the flow chart of  FIG. 3 ;  
         [0035]      FIG. 5  is an exemplary user interface for entering data to define the total number of sites within a network plan and the type of network (i.e., Voice Only, Data Only, or Voice and Data);  
         [0036]      FIG. 6  is an exemplary user interface for entering data to define a number of voice lines per site; total number of sites that have voice; percentage of time the voice lines are expected to be used per site; and the expected bandwidth per voice call;  
         [0037]      FIG. 7  is an exemplary user interface for entering data to specify a long term expected bandwidth per site based on a sharing ratio and an expected usage percentage of an upstream link by each site;  
         [0038]      FIG. 8  is an exemplary user interface for entering data to configure the upstream minimum CIR and additional CIR per remote used by the network planning system to plan for a minimum CIR for each remote that is different from the default CIR;  
         [0039]      FIG. 9  is an exemplary user interface for entering data to select an option to calculate the number of sites that can be supported automatically by selecting “Computed” from a pull-down menu or manually entering the number of remotes supported per upstream link;  
         [0040]      FIG. 10  is an exemplary user interface for entering data to specify the number of downstream links required per site from the user entering information including the long term expected average downstream bandwidth required per site, the expected sharing ratio of the downstream by each site, the desired CIR per remote on the downstream, the number of downstream sites with CIR, and the amount of reserved bandwidth to support multicast traffic on the downstream links;  
         [0041]      FIG. 11  is an exemplary user interface for entering data to define the size of carriers in the upstream and downstream links based on IP rates (TDM/TDMA Payload);  
         [0042]      FIG. 12  is an exemplary user interface for entering data to enter configurable parameters and informational fields relating to entire network such as if segmentation and re-assembly (SAR) is enable or disabled;  
         [0043]      FIG. 13  illustrates an example of a final network diagram provided by the network planning system;  
         [0044]      FIG. 14  illustrates another example of a final network diagram provided by the network planning system;  
         [0045]      FIG. 15  illustrates a third example of a final network diagram provided by the network planning system;  
         [0046]      FIG. 16  is an expanded view of the embedded processing block of the flow chart in  FIG. 3 ;  
         [0047]      FIG. 17  is an exemplary network information section, link budget information section, and cost information section of the network planning system;  
         [0048]      FIG. 18  is illustrates an example of an indication showing that an invalid parameter has been entered into the spreadsheet; and  
         [0049]      FIG. 19  is a block diagram of a computer that may be used to implement the network planning system.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]     Referring now to the drawings, one exemplary embodiment of the network planning system uses MICROSOFT EXCEL as a platform (or “operating system”) for the tool, although the system could be implemented using another standard spreadsheet or database. MICROSOFT EXCEL is preferred because it is the most popular spreadsheet used in industry and most end users already use a database or spreadsheet in normal business operations and thus are familiar with the interface. By using an industry standard spreadsheet as the interface, the end user need not spend his or her time learning a new operating system (or application), but rather can focus immediately on designing a system. In addition, using a standard platform (e.g., spreadsheet) decreases the “learning curve” associated with operating and understanding the network planning system since the user does not have to learn how to operate a new operating system, software package, or programming language to obtain a final network design. The end user only needs to understand the parameters of the shared satellite communications network he or she wishes to implement and the outputs received, detailing the implementation of the final network design that is produced by the network planning system.  
         [0051]      FIG. 2  is an example of a final network design that is produced by the network planning system and will be explained in detail following the explanation of the input network characteristics and parameters that are entered by the user and the calculations performed with the user inputs in producing the outputted final network design.  
         [0052]      FIG. 3  is a flow chart illustrating the parameters entered by the user in configuring the network that result in a final network design such as the example shown in  FIG. 2 . In steps S 100 , S 103 , S 105 , S 107  and S 109 , the user is prompted to enter the network type and size, voice parameters if a network type including voice operations is selected, upstream parameters, downstream parameters, and carrier parameters. The entered parameters are then processed in step S 111  using embedded calculations (to be discussed in more detail below) within the spreadsheet, and the process proceeds to step S 113  where the system provides a final network design based on the entered parameters and underlying equations.  
         [0053]      FIG. 4  is an exemplary embodiment of a spreadsheet corresponding to the flow chart of  FIG. 3  and is used herein to explain the details of the network planning system. It should be noted that the spreadsheet in  FIG. 4  includes 8 steps prompting the user to enter network characteristics and parameters. Each of the 8 steps is listed within the appropriate section of the flow chart shown in  FIG. 3 .  
         [0054]     The network planning system provides the user with a way to plan a network based on network characteristics and parameters. The system also provides a simple way to use sharing and overbooking ratios for both data and voice applications, and is designed to calculate bandwidth parameters in both the upstream and downstream direction based primarily on Internet Protocol (IP) data rate parameters. While the first embodiment is based on IP data rates only, it is understood that the network planning system is not limited to only IP data rates and may use other packet-switched or circuit-switched communication protocols. However, most customers&#39; parameters are based in IP throughputs and bandwidth parameters, and therefore the following description is explained in this first embodiment using IP data rates.  
         [0055]     Effective network planning involves an iterative process of determining the data rate for the upstream and downstream carriers. The iterative process can be attributed to bandwidth allocation calculations and fine-tuning of carriers based on data parameters and calculations. The network planning system allows the user to easily run several simulations using various possible network parameters to determine a final network design that not only meets the needs of the end customer but also meets the business goal of the user of the network planning system.  
         [0056]     This embodiment of the network planning system is explained for simplicity with the following underlying criteria: all calculations are made using IP data rates; sharing and overbooking ratios are based on applications and network parameters; all voice calculations are assumed to be bi-directional and thus are defined only in the upstream links, though the system calculates bandwidth needed in both directions; data bandwidth is in addition to the voice bandwidth parameters; CIR on the downstream or upstream links can be any data rate; CIR bandwidth is a part of voice and data parameters; and the system requires a minimum CIR to be allocated to every remote in the network. The minimum CIR is taken into consideration when the system bandwidth is computed. For explanation in this embodiment, the minimum CIR is one time-slot bandwidth. However, it is to be understood that the minimum bandwidth may adjusted lower allowing for a higher overbooking ratio.  
         [0000]     Explanation of User-Input Parameters  
         [0057]     As shown in  FIG. 5 , the user is prompted (for example, a property of a spreadsheet cell is set to be edited by the user) to define the type of network (i.e., Voice Only, Data Only, Voice and Data), and input the total number of sites that are expected within the desired shared satellite communications network. This type of network should be selected based on the desired nature of the network. If a network type is selected including voice operations the user is prompted (in this case the user is free to enter data into an appropriately labeled spreadsheet cell) to enter voice parameters S 103  as shown in the flow chart of  FIG. 3 . More specifically, the network parameters supplied in step  2  are used in Equation (1) (shown below) to calculate the bandwidth reserved to support the voice operations in both the upstream and downstream directions BW_V of the final network design provided by the network planning system. As shown in  FIG. 6 , the parameters include: the number of voice lines per site Num_Lines; total number of sites that have voice Num_Vsites; percentage of time the voice lines are expected to be used per site Percent_Vusage; and the expected bandwidth per voice call BW_per_V. The expected bandwidth per voice call BW_per_V depends on the Voice Codec used and if cRTP is enabled which compresses the headers and offers significant bandwidth savings. 
 
 BW   —   V=Num _Lines* Num   —   V sites*Percent —   V usage* BW _per —   V  
 
         [0058]     As shown in the flow chart of  FIG. 3 , the user also enters upstream parameters S 105 . Steps  3 ,  4 , and  5  of the exemplary spreadsheet shown in  FIG. 4  are used to explain the upstream parameters. As illustrated in  FIG. 7 , the information entered in step  3  is used to configure the upstream data bandwidth per remote and upstream oversubscription ratio. The oversubscription ratio is the ratio at which bandwidth is shared among multiple sites. For example, 64 Kbps shared at a 10:1 ratio, means that 1 in 10 sites is active at any given period of time. Accordingly, if only 1 site is active the site will receive 64 Kbps of bandwidth satisfying the bandwidth requirements for the user. The parameters entered in step  3  include the long-term expected bandwidth per site based on the oversubscription ratio and the expected usage percentage of an upstream link by each site. The expected usage percentage of an upstream link Upstream_Expected_Usage_Percentage for each site can be used to calculate the oversubscription ratio of an upstream link UR using Equation (2), or alternatively, the user can simply enter the oversubscription ratio directly. The oversubscription ratio is selected based on many factors that include the type of application being used, type of service offered, and customers using the network. 
 
 UR= 1/Upstream_Expected_Usage_Percentage  (2) 
 
         [0059]     Step  4 , as illustrated in  FIG. 8 , configures the upstream link&#39;s minimum CIR and additional CIR per remote. The CIR is the bandwidth guaranteed for each remote site regardless of the presence of traffic. The parameters shown in  FIG. 8  are used in conjunction with each other to plan for a minimum CIR for each remote that is different from the default CIR. In step  4  the user defines how many of the total sites need a minimum CIR that is different from the default, and the minimum bandwidth required by the sites with a minimum CIR different from the default. The advantage of this feature is that it allows the user to select a lower CIR, which allows for more burstable bandwidth or a higher oversubscription ratio. In step  4  the user also enters the desired CIR for each remote per upstream and the total number of sites with this desired CIR. Further, the user can implement dynamic CIR by using a CIR oversubscription ratio.  
         [0060]     Step  5 , as shown in  FIG. 9 , determines the number of sites that can be supported within one upstream link. The upstream link is discussed in more detail later and is defined by the user when entering the carrier parameters S 109  as shown in the flow chart of  FIG. 3 . In step  5 , the user may select “Manual” and enter the number of remotes supported by each upstream link directly, or alternatively, by selecting “Computed” the network planning system calculates the number of sites supported within one upstream link using Equations (3), (4), and (5).  
         [0061]     The number of remotes supported per upstream link will depend on the usable IP throughput per upstream carrier, the amount of bandwidth that is needed for the minimum CIR per site, static CIR bandwidth per CIR site, and the oversubscription ratio for the upstream link. In Equation (3) the reserved minimum bandwidth for each remote for the upstream link Res_min is calculated in the embedded processing block S 111  of  FIG. 3  using the following user-input parameters: the total number of sites TS; the number of sites with a non-default CIR UminS; the minimum bandwidth for the sites with the non-default CIR Umin; and the bandwidth per time slot BWTslot which is explained in detail later and is calculated using Equation (11). The reserved CIR bandwidth for each remote on the upstream link Res_Up_BW is calculated by processing the number of sites with CIR on the upstream link Usites, the total number of sites TS, and the upstream oversubscription ratio UR. Equation (3) calculates the number of remotes supported on the upstream link Rem_per_U by processing the upstream IP data rate for each upstream carrier Usize, the upstream data bandwidth for each site Up_BW, the upstream oversubscription ratio UR, reserved minimum bandwidth for each remote of the upstream link Res_min, the reserved CIR bandwidth for each remote on the upstream link Res_Up_BW. 
 
 Res   —   min =( TS−UminS )/ TS*BWT slot+( UminS/TS*BWT slot)/ Umin   (3) 
 
 Res _Up —   BW=U sites/ TS*UR   (4) 
 
 Rem _per —   U=U size/(UP —   BW*UR+Res   —   min+Res _Up —   BW )  (5) 
 
         [0062]     Step  6  illustrated in the spreadsheet of  FIG. 4  corresponds to the Enter Downstream Parameters block S 107  shown in the flow chart of  FIG. 3 . More specifically, step  6  as shown in  FIG. 10  is used to prompt the user to enter the parameters necessary per site on the downstream link. The number of downstream links supported is based on the downstream size defined by the user when entering the carrier parameters S 109  shown  FIG. 3  and discussed in greater detail later. In step  6  the user enters the following parameters: the long term expected average downstream bandwidth required per site Res_D_BW; the expected oversubscription ratio of the downstream for each site DR; the desired CIR per remote on the downstream D_BW; the number of downstream sites with CIR Dsites; and the amount of reserved bandwidth to support multicast traffic of the downstream M_BW. The above parameters are used in Equations (6) and (7) to determine the number of remotes supported per downstream link. 
 
 Res   —   D   —   BW=D sites/ TS*DR   (6) 
 
 Rem _per —   D =( D size− M   —   BW )/( D   —   BW* 1 /DR+Res   —   D   —   BW+BW   —   V )  (7) 
 
         [0063]     As shown in  FIG. 3 , the user is also prompted to enter the carrier parameters S 109  of the desired satellite network. The carrier parameters are defined in steps  7  and  8  in the exemplary spreadsheet  FIG. 4 . As illustrated in  FIGS. 4 and 11 , step  7  is used to define the size of the carriers in the upstream and downstream links based on the IP rates (TDM/TDMA Payload). In step  7  the user enters the upstream IP data rate IP_Data_Rate and downstream IP data rate D_IP_Data_Rate. Alternatively, the user may choose to only enter the upstream IP data rate IP_Data_Rate and have the network planning system calculate the necessary downstream IP data rate based on the upstream IP data rate and parameters entered during steps  1 - 7  of the exemplary spreadsheet shown in  FIG. 4 . The upstream carrier value is generally dictated by the antenna and Bus Unit Controller (BUC) size parameters. The user is also prompted to select an upstream FEC option and downstream FEC option FEC bits. The FEC options are used in the embedded equations to calculate the carrier bandwidths and time slot specific bandwidths. The upstream and downstream FEC options provide greater system flexibility and network optimization. Further, the user is directed to select a guard band used to calculate the required bandwidth for the upstream and downstream links RBW shown in  FIG. 11 . It should be noted that this embodiment of the present invention assumes a bandwidth-limited requirement only. Conversely, if there is a Power Equivalent Bandwidth required, the user should ensure the correct amount of bandwidth is acquired. The information entered by the user in step  7  is used in Equations (8), (9), and (10) to determine the transmission rates Tran_Rate and required bandwidth RBW illustrated in  FIG. 11 . The transmission rate Tran_Rate calculated by the network planning system includes all bits needed in a carrier. This embodiment of the network planning system is Quadrative Phase-Shift Keying QPSK_Modulation, therefore the transmission rate calculated is twice that of the symbol rate. It should be noted that the TDMA_and_LayerTwo_Overhead consists of variables such as demand information, encryption information, and packet assembly and disassembly used by the network planning system. 
 
Info_Rate= TDMA _and_LayerTwo_Overhead+ IP _Data_Rate  (8) 
 
 Tran _Rate= FEC  bits+ Info _Rate  (9) 
 
 RBW=Trans _Rate* C Spacing/ QPSK _Modulation  (10) 
 
         [0064]     As shown in  FIG. 12 , step  8  prompts the user to enter the frame length Frame_Length for a network. For a given network, the frame-length is defined by the downstream link and is fixed for all upstream links. When the size of the downstream is set, the network planning system of this embodiment calculates available frame lengths, which can then be chosen from a dropdown list. For most networks the frame length Frame_Length is set to approximately 125 milli-seconds. The parameters entered in step  8  are used to calculate how many time slots are available in each upstream link and the bandwidth available for each time slot BWTslot. Further, in step  8  the user is prompted to select if Segmentation and Re-assembly (SAR) is enable or disabled. If SAR is enabled, there is an additional overhead in each time slot. This decreases the bandwidth per time slot BWTslot. Since the calculations are based on IP data rate parameters Payload_Capacity_TS in this embodiment, the total slots will increase to accommodate the reduction in bandwidth per time slot BWTslot. 
 
 BWT slot=(Payload_Capacity —   TS *100/Frame_Length  (11) 
 
 Final Network Diagrams Output by Network Planning System 
 
         [0065]      FIGS. 13, 14 , and  15  are variants of an example illustration of the Final Network Diagrams provided based on the network parameters entered in steps  1 - 8  of this embodiment. The downstream links  200  are shown as the number of networks (large carriers). If the number of networks is greater than 1 (meaning that multiple downstream links are required to support the desired number of upstream links), then multiple downstream carriers are displayed overlapping each other as shown in  FIG. 14 . Also, if the number of networks is greater than 1, then the upstream links  203  have to be split between all the downstream links  200 . The upstream links  203  are shown as multiple carriers. (the smaller carriers) The total number of upstream carriers  205  is displayed above the smaller carriers as shown in  FIGS. 13-15 . For example, there are 9 upstream carriers in  FIG. 13 . Since all upstream carriers are assumed to be of the same size, only one of the carriers TDMA frame format  209  is shown. The TDMA frame format is displayed in a number of time-slots. The total number of timeslots  207  is shown towards the right and above the TDMA frame format  209 . In  FIG. 13 , there are 87 time slots. The remotes in the final network design are distributed among all upstream carriers. In the example of  FIG. 13 , each carrier holds 28 remotes. In  FIG. 13 , the number of remotes a carrier holds is displayed under the carriers and below the TDMA Frame format  209 .  
         [0000]     Embedded Calculations  
         [0066]     The parameters entered by the user are processed in the Embedded Processing block shown in  FIG. 3 .  FIG. 16  is an expanded flow chart illustrating the equations providing the information displayed in  FIG. 17 .  
         [0067]     The network information section illustrated in  FIG. 17  provides the final network design information used for implementing a physical layer of the desired satellite network system. This information includes: the total number of remotes per upstream Rem_per_U calculated using equations (12), (13), and (14); the total number of upstream links Num_of_U calculated using Equation (15); the total number of downstream links Num_of_D calculated using Equation (16) that includes a Ceiling variable embedded within the spreadsheet; the burstable bandwidth per upstream link Burst_Bandwidth calculated using Equation (17); and any additional remotes that can be supported by the downstream links; and any additional remotes that can be supported by the upstream links. 
 
 Res   —min =( TS−UminS )/ TS*BWT slot+( UminS/TS*BWT slot)/ Umin   (12) 
 
 Res _Up —   BW=U sites/ TS*UR   (13) 
 
 Rem _per —   U=U size/(Up —   BW*UR+Res   —   min+Res _Up —   BW )  (14) 
 
 Num _of —   U=TS/Rem _per —   U   (15) 
 
 Num _of —   D =Ceiling*( D size/ Rem _per —   D )  (16) 
 
Burst_Bandwidth= U size− Rem _per —   U*BWT slot  (17) 
 
         [0068]     The remotes per upstream communication channel are distributed among all upstream links that are needed to fulfill the parameters. In the example illustrated in  FIG. 13 , each upstream link can support 28 remotes. This means that one would need at least 9 upstream links to support a total number of 250 sites. If there are 9 upstream links, then the tool attempts to distribute the remotes equally among all the upstream links.  
         [0069]     The value of “Additional Remotes Supported By Downstream” indicates whether or not the downstream carrier has been sized appropriately based on the voice, upstream, downstream, and carrier parameters entered by the user. If this value is greater than 0, then the size of the downstream carrier can be reduced, thus decreasing the overall bandwidth required. If the downstream links could support additional sites, this indicates the downstream IP data rate could be reduced and still support the user-entered parameters. This allows the user to fine tune a desired network.  
         [0070]     The value of “Additional Remotes Support By Upstreams” indicates whether or not the upstream carriers have been sized appropriately, based on the voice, upstream, downstream, and carrier parameters entered by the user. Similarly, if this value is greater than 0, then the size of the upstream carriers can be reduced, thus decreasing the overall bandwidth required. In this example, each upstream carrier can support 29 remotes with 400 kbps. Since there are 250 sites, then the minimum number of carriers is 9. Thus the upstream links could support a total of 261 sites, which means 11 more sites could be supported by the upstream links. Therefore, the designer can reduce the size of the upstream carriers to match the total number of sites and bandwidth required. A value of 0, indicates a properly sized carrier according to the voice, upstream, downstream, and carrier parameters entered by the user.  
         [0071]     The NMS and Link Budget Information section illustrated in  FIG. 17  displays the amount of required bandwith on the satellite for all upstream and downstream carriers. This information is based on a bandwith-limited requirement. If desired satellite network has a power equivalent bandwith requirement, the user can also enter the additional power required for either the downstream of the upstream communication channels. The amount of bandwith required T_BW is calculated using Equation (16). 
 
 T   —   BW =( DRBW*Ad   —   D*Num   —   DCs )+( URBW*Ad   —   U*Num   —   UCs )  (18) 
 
         [0072]      FIG. 17  also illustrates a cost analysis section provided in this embodiment of the network planning system. The total network planning system calculates the total monthly cost per Mhz of bandwidth T_Monthly_Cost and the total monthly cost per site T_Monthly_Cost_per_site of the final network design provided by the network planning system using Equations (15) and (16). This information is calculated from an estimate of the monthly cost of bandwidth Cost_per_Mhz that is entered by the user. 
   T _Monthly_Cost= RBW *Cost_per_Mhz  (19)    T _Monthly_Cost_per_site= T _Monthly_Cost/ TS   (20)  
         [0073]     The first embodiment of the network planning system also indicates to the user when invalid parameters are entered into the spreadsheet. This further simplifies the network planning process. When an invalid parameter is entered, the user is notified by an indicator displayed next to the invalid input as shown in  FIG. 18 . For example, this embodiment indicates that the number of voice sites should be less than the number of total sites.  
         [0074]     The first embodiment of the network planning system also provides the user a worksheet that displays all information in text format for input into proposals or for handouts.  
         [0075]     Further, a conversion tool is included in this first embodiment that provides a worksheet that can be used to determine IP rates from either “Information Rate,” “Transmission Rate,” or “Required Bandwidth.”  
         [0000]     Computer and System  
         [0076]     This invention may be implemented using a conventional general purpose computer or micro-processor programmed according to the teachings of the present invention, as will be apparent to those skilled in the computer art. Appropriate software can readily be prepared by programmers of ordinary skill based on the teachings of the present disclosure, as will be apparent to those skilled in the software art.  
         [0077]     A computer  100  as shown in  FIG. 19  may implement the systems, methods and computer program product of the present invention, wherein the computer housing  102  houses a motherboard  104  which contains a CPU  106 , memory  108  (e.g., DRAM, ROM, EPROM, EEPROM, SRAM, SDRAM, and Flash RAM), and other optical special purpose logic devices (e.g., ASICS) or configurable logic devices (e.g., GAL and reprogrammable FPGA). The computer  100  also includes plural input devices, (e.g., keyboard  122  and mouse  124 ), and a display card  110  for controlling a monitor  120 . Additionally, the computer  100  may include a floppy disk drive  114 ; other removable media devices (e.g. compact disc  119 , tape, and removable magneto-optical media (not shown)); and a hard disk  112  or other fixed high density media drives, connected using an appropriate device bus (e.g., a SCSI bus, an Enhanced IDE bus, or an Ultra DMA bus). The computer may also include a compact disc reader  118 , a compact disc reader/writer unit (not shown), or a compact disc jukebox (not shown), which may be connected to the same device bus or to another device bus.  
         [0078]     As stated above, the system includes at least one computer readable medium. Examples of computer readable media are compact discs  119 , hard disks  112 , floppy disks, tape, magneto-optical disks, PROMs (e.g., EPROM, EEPROM, Flash EPROM), DRAM, SRAM, SDRAM, etc. Stored on any one or on a combination of computer readable media, the present invention includes software for controlling both the hardware of the computer  100  and for enabling the computer to interact with a human user. Such software may include, but is not limited to, device drivers, operating systems and user applications, such as development tools. Such computer readable media further includes the computer program product of the present invention for performing the inventive method herein disclosed. The computer code devices of the present invention can be any interpreted or executable code mechanism, including but not limited to, scripts, interpreters, dynamic link libraries, Java classes, and complete executable programs. Moreover, parts of the processing of the present invention may be distributed for better performance, reliability, and/or cost. For example, plural contingencies can be calculated in parallel to determine portions of the uncertain costs simultaneously and the results summed at the end.  
         [0079]     The invention may also be implemented by the preparation of application specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be readily apparent to those skilled in the art.  
         [0080]     Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.