Computer-implemented inbuilding prediction modeling for cellular telephone systems

• US 6,088,522 A
• Filed: 07/31/1997
• Issued: 07/11/2000
• Est. Priority Date: 07/31/1997
• Status: Expired due to Term

• Current Assignee: Cellco Partnership, Inc. (Verizon Communications Inc.)
• Original Assignee: Airtouch Communications, Inc. (Vodafone Group PLC)
• Inventors: Lee, Jau Young, Lee, William Chien-Yeh
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): Fiul, Dan
• Application Number:
  US08/904,309
• Time in Patent Office: 1,076 Days
• Field of Search: 364/578, 395/500, 395/500.23, 395/500.34, 395/500.41, 395/500.42, 375/224, 455/63, 455/454, 370/338, 370/349
• US Class Current: 703/13
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/3913 Predictive models, e.g. based on neural network models
• CPC Class Codes: H04W 16/20 for indoor coverage or short range network deployment

Abstract

A computer-implemented modeling tool for cellular telephone systems predicts signal strength under real conditions within a building, by considering the effects of inter-building and intra-building structures on transmitted signals. The modeling tool gives more accurate predictions under line of sight conditions, when obstructions occur due to inter-building and intra-building structures.

Claims

1. A computer-implemented method for modeling a wireless commnunications system comprising a transmitter having an antenna and a receiver having an antenna located at a distant location from the transmitter antenna, comprising the steps of:

(a) collecting data concerning the operation of the transmitter and receiver, and storing the collected data in a computer,

(b) computing a strength of a signal received at the receiver antenna from the transmitter antenna using the stored data, wherein the strength of the signal is computed by determining a line of sight signal strength between the transmitter antenna and the receiver antenna, by detining effects on the signal strength from one or more inter-building and intra-building structures between the transmitter antenna and the receiver antenna, and by modifying the line of sight signal strength using the determined effects; and

(c) outputting one or more reports from the computer representing the modified line of sight signal strength, wherein the reports are used in operating the wireless communications system.

2. The method of claim 1, wherein the computing step further comprises the step of computing a strength P_r of a signal received at the receiver antenna from the transmitter antenna using the stored data, wherein the strength P_r is computed as:

space="preserve" listing-type="equation">P.sub.r =P.sub.t +G.sub.t -L.sub.los -L.sub.room -L.sub.outside +G.sub.r

where;

P_r is a signal strength at the receiver antenna,

P_t is a transmitter power,

G_t is a transmitter antenna gain,

L_los is a loss under line of sight,

L_room is a loss due to intra-building effects,

L_outside is a loss due to inter-building effects, and

G_r is a receiver antenna gain.

3. The method of claim 2, wherein the computing step further comprises the steps of:

(1) calculating a line of sight loss L_los for each segment d_i ;

##EQU6## where n is a number of segments, λ

is a wavelength of a transmitted signal, and d_i is a length of segment I; and

(2) accumulating the line of sight loss L_los for all segments d_i as L_los.

4. The method of claim 2, wherein the computing step further comprises the steps of:

(1) calculating a standard room loss L_room of each segment i that intersects a standard room as;

space="preserve" listing-type="equation">L.sub.room =m.sub.room log d.sub.i

where m_room is a slope of the standard room, and d_i is a length of segment i; and

(2) accumulating the standard room loss L_room for all segments d_i as L_room.

5. The method of claim 2, wherein the computing step further comprises the steps of:

(1) calculating a special room loss L_specialroom of each segment i that intersects a special room as;

space="preserve" listing-type="equation">L.sub.SpecialRoom =m.sub.SpecialRoom log d.sub.i

where;

m_SpecialRoom is a slope of the special room, and d_i is a length of the segment I; and

(2) accumulating the special room loss L_SpecialRoom for all segments d_i as L_SpecialRoom.

6. The method of claim 2, wherein the computing step further comprises the steps of:

(1) calculating an outside loss L_outside of each segment i that is outside the building as;

space="preserve" listing-type="equation">L.sub.outside =Δ

+20 log d.sub.i

where d_i is a length of the segment i, and Δ

is an additional loss; and

(2) accumulating the outside loss L_outside for all segments d_i as L_outside.

7. An article of manufacture comprising a program storage medium readable by a computer having a memory, the medium tangibly embodying one or more programs of instructions executable by the computer to perform method steps for synchronizing elements of an object-oriented system, the method comprising the steps of:

(a) collecting data concerning the operation of the transmitter and receiver, and storing the collected data in a computer;

(b) computing a strength of a signal received at the receiver antenna from the transmitter antenna using the stored data, wherein the strength of the signal is computed by determining a line of sight signal strength between the transmitter antenna and the receiver antenna, by determining effects on the signal strength from one or more inter-building and intra-building structures between the transmitter antenna and the receiver antenna, and by modifying the line of sight signal strength using the determined effects; and

(c) outputting one or more reports from the computer representing the modified line of sight signal strength, wherein the reports are used in operating the wireless communications system.

9. The article of manufacture of claim 7, wherein the computing step further comprises the step of computing a strength P_r of a signal received at the receiver antenna from the transmitter antenna using the stored data, wherein the strength P_r is computed as:

space="preserve" listing-type="equation">P.sub.r =P.sub.t +G.sub.t -L.sub.los -L.sub.room -L.sub.outside +G.sub.r

where;

P_r is a signal strength at the receiver antenna,

P_t is a transmitter power,

G_t is a transmitter antenna gain,

L_los is a loss under line of sight,

L_room is a loss due to intra-building effects,

L_outside is a loss due to inter-building effects, and

G_r is a receiver antenna gain.

10. The article of manufacture of claim 9, wherein the computing step furter comprises the steps of:

(1) calculating a line of sight loss L_los for each segment d_i ;

##EQU7## where n is a number of segments, λ

is a wavelength of a transmitted signal, and d_i is a length of segment I; and

(2) accumulating the line of sight loss L_los for all segments d_i as L_los.

11. The article of manufacture of claim 9, wherein the computing step further comprises the steps of:

(1) calculating a standard room loss L_room of each segment i that intersects a standard room as;

space="preserve" listing-type="equation">L.sub.room =m.sub.romm log d.sub.i

where m_room is a slope of the standard room, and d_i is a length of segment i; and

(2) accumulating the standard room loss L_room for all segments d_i as L_room.

12. The article of manufacture of claim 9, wherein the computing step further comprises the steps of:

(1) calculating a special room loss L_specialroom of each segment i that intersects a special room as;

space="preserve" listing-type="equation">L.sub.SpecialRoom =m.sub.SpecialRoom log d.sub.i

where m_SpecialRoom is a slope of the special room, and d_i is a length of the segment I; and

(2) accumulating the special room loss L_SpecialRoom for all segments d_i as L_SpecialRoom.

13. The article of manufacture of claim 9, wherein the computing step further comprises the steps of:

(1) calculating an outside loss L_outside of each segment i that is outside the building as;

space="preserve" listing-type="equation">L.sub.outside =20+20 log d.sub.i

where d_i is a length of the segment i; and

(2) accumulating the outside loss L_outside for all segments d_i as L_outside.

8. A computerized apparatus for synchronizing elements of an object oriented system, comprising:

(a) a computer having a memory;

(b) means, performed by the computer, for collecting data concerning the operation of the transmitter and receiver, and storing the collected data in a computer;

(c) means, performed by the computer, for computing a strength of a signal received at the receiver antenna from the transmitter antenna using the stored data, wherein the strength of the signal is computed by determining a line of sight signal strength between the transmitter antenna and the receiver antenna, by determining effects on the signal strength from one or more inter-building and intra-building structures between the transmitter antenna and the receiver antenna, and by modifying the line of sight signal strength using the determined effects; and

(d) means, performed by the computer, for outputting one or more reports from the computer representing the modified line of sight signal strength, wherein the reports are used in operating the wireless communications system.

14. The apparatus of claim 8, wherein the means for computing further comprises means for computing a strength P_r of a signal received at the receiver antenna from the transmitter antenna using the stored data, wherein the strength P_r is computed as:

space="preserve" listing-type="equation">P.sub.r =P.sub.t +G.sub.t -L.sub.los -L.sub.room -L.sub.outside +G.sub.r

where;

P_r is a signal strength at the receiver antenna,

P_t is a transmitter power,

G_t is a transmitter antenna gain,

L_los is a loss under line of sight,

L_room is a loss due to intra-building effects,

L_outside is a loss due to inter-building effects, and

G_r is a receiver antenna gain.

15. The apparatus of claim 14, wherein the means for computing further comprises:

(1) means for calculating a line of sight loss L_los for each segment d_i ;

##EQU8## where n is a number of segments, λ

is a wavelength of a transmitted signal, and d_i is a length of segment I; and

(2) means for accumulating the line of sight loss L_los for all segments d_i as L_los.

16. The apparatus of claim 14, wherein the means for computing further comprises:

(1) means for calculating a standard room loss L_room of each segment i that intersects a standard room as;

space="preserve" listing-type="equation">L.sub.room =m.sub.room log d.sub.i

where m_room is a slope of the standard room, and d_i is a length of segment i; and

(2) means for accumulating the standard room loss L_room for all segments d_i as L_room.

17. The apparatus of claim 14, wherein the means for computing further comprises:

(1) means for calculating a special room loss L_specialroom of each segment i that intersects a special room as;

space="preserve" listing-type="equation">L.sub.SpecialRoom =m.sub.SpecialRoom log d.sub.i

where m_SpecialRoom is a slope of the special room, and d_i is a length of the segment I; and

(2) means for accumulating the special room loss L_SpecialRoom for all segments d_i as L_SpecialRoom.

18. The apparatus of claim 14, wherein the means for computing further comprises:

(1) means for calculating an outside loss L_outside of each segment i that is outside the building as;

space="preserve" listing-type="equation">L.sub.outside =20+20 log d.sub.i

where d_i is a length of the segment i; and

(2) means for accumulating the outside loss L_outside for all segments d_i as L_outside.