Method of polling to determine service needs and the like

• US 5,130,983 A
• Filed: 03/27/1990
• Issued: 07/14/1992
• Est. Priority Date: 03/27/1990
• Status: Expired due to Fees

• Current Assignee: Horace W. Heffner III
• Original Assignee: Horace W. Heffner III
• Inventors: Heffner, Horace W. III
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Ton, Dang
• Application Number:
  US07/499,971
• Time in Patent Office: 840 Days
• Field of Search: 370/85.6, 370/85.4, 370/85.8, 370/108, 370/94.3, 370/104.1, 370/95.2, 370/60, 370/94.1, 370/85.3, 370/85.4, 370/85.1, 340/825.08, 340/825.02, 340/825.5, 340/825.51, 340/825.52, 340/825.05, 340/825.54, 340/505, 340/518, 395/158, 395/148, 395/725, 395/275
• US Class Current: 370/449
• CPC Class Codes: H04L 12/40163 by assigning priority to messages according to a message field
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling

Abstract

Tis method provides high utilization collision free access to a digital pulse communications medium with priority provided by message class and/or terminal type, regardless of network topology. This is accomplished by utilizing a controller which broadcasts a series of polling frames to all terminals, the response to each of which is a single bit (pulse) from any terminal remaining eligible to respond. All responses to a poll are logically OR'"'"'ed by the network to provide a combined response frame at the controller, thus making the process ambivalent to collisions. A polling frame and associated response frame, called a polling cycle, determines one digit of a selected address. A terminal not selected in a given cycle is blocked from responding further, until its high order digit(s) are again selected. Each polling cycle is therefore context sensitive, thus maximizing the information flow per poll and minimizing data flow and network travel time per terminal selection. Each polling frame specifies the value of the address digit being tested, thereby giving the controller complete control of priority of network addresses to receive service. To provide priority by message class, the additional message class bits are prefixed to each terminal address, providing a unique address for each terminal/message class combination. Each terminal is then free to modify the prefix of its own address to specify message priority.

Claims

1. A polling method for a two way communication system comprised of a controller and a multiplicity of terminals, each said terminal having a unique binary address code of a common length of at least two bits, and said terminals having the capability of detecting and responding to codes sent from said controller, the terminal responses being binary codes which are observed by said controller as a single combined response code, said single combined response code being equivalent to the result of combining all said responses through logical summing, the objective of said polling method being the selection of an address of a terminal requiring service by storing the selected address in a work area in said controller and having the terminal with said selected address able to determine it has been selected, said controller including means to determine at any stage of the polling process a preferred value of a digit of said selected address, said polling method comprising the steps of:

a) having said controller establish a pointer designating a polled for digit, said polled for digit designated initially as the first digit of said terminal addresses and having said controller notify each of said terminals that a polling sequence is beginning, each terminal requiring service at the tome of the notification of polling sequence start being eligible to respond to future polls of said polling sequence, other terminals being ineligible to respond during said polling sequence;

b) having said controller broadcast at least one query poll to all terminals, said poll corresponding to said polled for digit of the address and said poll identifying said preferred value of said polled for digit;

c) having a simultaneous response from each said terminal still eligible to respond which has in said polled for digit of its address said preferred value, these terminals being called responding terminals;

d) having said controller wait for said single combined response code from said responding terminals, said single combined response code being affirmative if any terminal responded, negative otherwise;

e) having said controller store in said polled for digit of said work area representing said selected address said preferred value if said single combined response code is affirmative, the opposite of said preferred value otherwise, this value being called a selected value of the polled for digit;

f) having said controller establish the next digit as the polled for digit and repeating steps b through e with said query poll of step b indicating said selected value of the polled for digit most recently determined in step e, any said eligible terminal becoming ineligible to respond further in said current polling sequence if said eligible terminal does not have said selected value of the polled for digit in said polled for digit most recently determined in step e;

g) repeating step f until each digit of said addresses of said common address length has been polled and said selected values stored in said work area, so a complete address is stored in said work area;

h) having the controller with a query poll indicate said selected value of the polled for digit most recently determined in step e, which is the last digit to be selected;

i) having respond the one terminal still eligible to respond which has in said polled for digit of its address said selected value of the digit most recently determined in step e, this terminal being the single terminal that corresponds to said complete stored address and is therefore notified of its selection by virture of its response, and said complete address identifies said terminal requiring service, otherwise, if there is no response to the poll of step h, no terminal requires service.

2. The method of claim 1 wherein the notification that a polling sequence is beginning in step a is included in the query poll of step b.

3. The method of claim 1 wherein the preferred value of each digit is determined prior to the polling sequence and included in the notification that a polling sequence is beginning in step a instead of in the individual query poll of step b.

4. The method of claim 1 wherein the preferred value of each digit is fixed and contained in each terminal and the controller instead of being included in the individual query poll of step b.

5. THe method of claim 1 wherein predetermined values for specific digits are selected and codified in the notification that a polling sequence is beginning in step a instead of performing steps b through e to determine the values for said specific digits.

6. A polling method for a communication system having a controller and a multiplicity of terminals, each said terminal having a unique binary address code of a common length comprised of at least two bits, and said terminals and controller having the capability of detecting and responding to codes sent from the controller or any of said terminals, said terminal responses comprised of binary codes which, when in response to a specific poll, are observed by said controller and terminals as a single response code, said single response code being equivalent to the result of combining all said responses through logical summing, the objective of said polling method being the selection of the address of a terminal requiring service by storing said selected address in a work area in said controller and having the terminal with said selected address able to determine it has been selected, said controller including means to determine at any stage of the polling process a preferred value of a digit of said selected address, said polling method comprising the steps of:

a) having said controller establish a pointer designating a polled for digit as the first digit of said addresses and having said controller notify each of said terminals that a polling sequence is beginning, each terminal requiring service at the time of the notification of polling sequence start being eligible to respond to future polls of said polling sequence, other terminals being ineligible to respond during said polling sequence;

b) having said controller broadcast at least one query poll to all terminals, said poll corresponding to said polled for digit of the address and said poll identifying said preferred value of said polled for digit;

c) having respond simultaneously each said terminal still eligible to respond which has in said polled for digit of its address said preferred value, these terminals being called responding terminals;

d) having said controller and all said eligible terminals wait for said single combined response code from said responding terminals, said single combined response code being affirmative if any terminal responded, negative otherwise;

e) having said controller store in said polled for digit of said selected address stored in said work area said preferred value if said single combined response code is affirmative, the opposite of said preferred value otherwise, this value being called a selected value of the polled for digit;

f) having each said eligible terminal becoming ineligible to respond further in said current polling sequence if said eligible terminal does not have said preferred value in said polled for digit of the prior poll in said unique binary address code of said eligible terminal if said single combined response code is affirmative;

g) having said controller establish the next digit as the polled for digit and repeating steps b through f;

h) repeating step g until each digit of said addresses of said common address length has been polled and said selected values stored in said work area, so a complete address is stored in said work area;

i) having respond the terminal still eligible to respond this terminal being the single terminal that corresponds to said complete stored address and is therefore notified of its selection by virtue of its eligibility at the conclusion of step h, otherwise, if there is no response no terminal requires service.

7. The method of claim 6 wherein the notification that a polling sequence is beginning in step a is included in the query poll of step b.

8. The method of claim 6 wherein the preferred value of each digit is determined prior to the polling sequence and included in the notification that a polling sequence is beginning in step a instead of in the individual query poll of step b.

9. The method of claim 6 wherein the preferred value of each digit is fixed and contained in each terminal and the controller instead of being included in the individual query poll of step b.

10. The method of claim 9 wherein the query poll of step b consists of a single bit.

11. The method of claim 6 wherein predetermined values for specific digits are selected and codified in the notification that a polling sequence is beginning in step a instead of determining the values for said specific digits in steps b through e.

12. The method of claim 11 wherein the query poll of step b consists of a single bit.

13. A polling method for a communication system comprised of a controller and a multiplicity of terminals, each said terminal having a unique address code of a common length of at least two digits, said digits being expressed in a radix, called the address radix, and said terminals having the means of detecting and responding to codes sent from said controller, said terminal responses being binary codes consisting of a number of bits equal to the address radix number, only one which is a 1, which are observed by said controller as a combined multiple response code consisting of the address radix number of bits, said combined multiple response code being equivalent to the result of combining all said terminal response codes through a bit wise logical summing, the objective of said polling method being the determination and storage of the addresses of every terminal requiring service at the start of an application of said polling method, by storing the selected addresses in a selected terminal queue work area in said controller, said polling method comprising the steps of:

a) having said controller initialize a cell indicating a polled for digit, said polled for digit initially being digit 0, and having said controller initialize a cell indicating a designated digit value, its initial value unimportant;

b) having said controller broadcast a poll frame to all said terminals which indicates to said terminals said polled for digit and said designated digit value;

c) if said polled or digit of step b is 0, having each terminal requiring service at the time of the broadcast of said poll frame respond by sending a response code consisting of a 1 in the bit of the response code corresponding to the value of the first digit of the terminal'"'"'s address code, each said terminal marking itself as matching through said polled for digit 0;

d) if said polled for digit of step b is greater than 0, having each terminal which has marked itself matching through the previous polled for digit and which also in the current polled for digit of its address matches said designated digit value, mark itself as matching through the current polled for digit, and send a response code consisting of a 1 in the bit of said response code corresponding to the value of the next digit of the terminal'"'"'s address;

e) having said controller wait for said combined multiple response code;

f) for each bit of said combined multiple response code which is 1, having said controller push a pair of values on a work stack, said pair of values consisting of the number of the response code bit which is 1, and said polled for digit plus 1;

g) if said work stack is empty, having said controller proceed back to step a, otherwise having the controller remove a pair of values from said work stack, these becoming the new said polled for digit and said designated digit value;

h) having said controller store into a work area containing a partially selected address said designated value in the digit of the selected address indicated by the polled for digit;

i) if said selected address is complete, having the controller put said selected address on said selected terminal queue work area and proceeding to step g, otherwise, proceeding to step b.

14. The method of claim 13 wherein said combined multiple response code is obtained by transmitting each bit of said terminal response codes on a separate channel.

15. The method of claim 13 wherein said combined multiple response code is obtained by having each responding terminal send its single bit response with a delay appropriate to have said bit logically summed into the appropriate bit of the single combined response code.

16. The method of claim 15 wherein said delay is determined through an initial calibration session between said controller and each of said terminals individually, wherein said controller determines the natural delay of the terminal being calibrated and sends it a compensating additional delay which, when added to the natural delay, results in a delay which is the maximum acceptable delay for any terminal, thus aligning the response of every terminal to the same delay as viewed from said controller, said terminals then always delaying the compensating interval plus any required delay to place a response bit in the appropriate bit of said combined multiple response code.

17. The method of claim 13 wherein said combined multiple response code is obtained by having said controller issue a bit designating poll frame prior to transmission of each bit of said combined multiple response code

18. The method of claim 17 wherein said bit designating poll frame consists of a single bit.