Method of indoor radio planning

• US 20080057873A1
• Filed: 08/29/2006
• Published: 03/06/2008
• Est. Priority Date: 08/29/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Huang, Jian, Xiang, Zhe, Zhang, Hang Jin, Song, Song
• Granted Patent: US 7,881,720 B2
• Time in Patent Office: Days
• US Class Current: 455/67.11
• CPC Class Codes: H04W 16/20 for indoor coverage or short range network deployment

Abstract

A radio planning method and apparatus for determining the setting scheme of base stations in an indoor environment is provided. A radio signal propagation model is generated including a theoretical attenuation part and an environment affecting part. Through on-site measurements, a site radio signal propagation characteristics database is constructed combining the indoor radio signal propagation model and on-site measurement results. Based on the environment-dependent database, a radio signal map representing the radio signal distribution to be generated in the site in the case of placing any type of base station in any position is generated, using the indoor radio signal propagation model. By applying a signal-to-quality mapping, the distribution of a specific quality metric for any base station is obtained. Thus, by inputting different base station parameters, respective radio signal maps can be generated to optimize positioning of base stations.

Claims

1. A radio planning method for determining optimal positioning of base stations in an indoor environment, comprising the steps of:

defining a plurality of transmitting points for placing at least one base station and at least one receiving point for receiving signals transmitted by the at least one base station;

obtaining environment affecting factors indicative of the effect of the indoor environment on the radio signal propagated from each transmitting point to each receiving point by performing actual measurements with a plurality of base stations placed at said plurality of transmitting points and wherein a selected type of base station is placed at one transmitting point;

for a given one of said transmitting points and at least one type of base station, calculating non-environment-affecting theoretical values of signal strength to be received at each receiving point according to a non-environment-affecting theoretical attenuation model corresponding to the type of base station; and

generating a map of signal strength received at each of said at least one receiving point on the basis of said non-environment-affecting theoretical values and said environment affecting factors.

2. The method according to claim 1, wherein said step of obtaining said environment affecting factor between a transmitting point and a receiving point by performing actual measurements comprises the steps of:

placing a selected type of base station at said transmitting point;

measuring received signal strength at said receiving point;

calculating the theoretical value of signal strength received at said receiving point according to the theoretical attenuation model corresponding to said selected type of base station; and

subtracting said theoretical value from said received signal strength to obtain said environment affecting factor.

3. The method according to claim 1, wherein in addition to said environment affecting factors obtained by said actual measurements, additional environment affecting factors are deduced from the obtained environment affecting factors.

4. The method according to claim 3, further comprising the step of selecting environment affecting factors to be obtained by actual measurements using a lazy sampling algorithm.

5. The method according to claim 1, further comprising the step of:

mapping the generated radio signal strength maps into QoS (Quality of Service) maps.

6. The method according to claim 5, wherein a QoS objective of the indoor radio planning is at least one of positioning accuracy and accuracy and response time of an identification system and wherein said mapping comprises generating said QoS maps according to said QoS objective.

7. The method according to claim 5, further comprising the steps of:

evaluating the QoS maps of a plurality of setting schemes of base stations in which at least one selected type of base station is placed at said at least one transmitting point; and

selecting an optimal setting scheme of base stations according to the evaluating results.

8. The method according to claim 1, wherein said theoretical attenuation model is related to the physical specifications of base stations, said physical specifications of base stations including at least one of the power magnitude of the base station antenna and the opening direction and opening type of the base station antenna when the antenna is a directional antenna.

9. The method according claim 8, wherein

a first theoretical attenuation model formula for the theoretical attenuation model corresponding to an omni-directional antenna is:

P_A(B)[dBm]=C−

K log(|AB|)

and a second theoretical attenuation model formula corresponding to a directional antenna is;

P_A(B)[dBm]=C−

(K₁+θ

K₂)log(|AB|)

where A represents the transmitting point, B represents the receiving point, P_A(B) represents the strength of the radio signal from the transmitting point A received at the receiving point B, |AB| represents distance between the transmitting point A and the receiving point B, θ

represents an angle between the main axis of the directional antenna and the connecting line from the transmitting point A to the receiving point B, and C, K, K1, K2 are parameters related to physical specifications of the base station.

10. A radio planning apparatus for determining optimal positioning of base stations in an indoor environment, wherein at least one transmitting point for placing base station and at least one receiving point for receiving signals transmitted by the base stations are defined in said indoor environment, the apparatus comprising:

an environment affecting factor obtaining means for obtaining environment affecting factors indicative of the effect of the indoor environment on the radio signal propagated from each transmitting point to each receiving point by performing actual measurements with a plurality of base stations placed at transmitting points and wherein a selected type of base station is placed at one transmitting point;

an non-environment-affecting theoretical attenuation model calculating means for calculating at least one non-environment-affecting theoretical value of signal strength to be received at each receiving point according to a non-environment-affecting theoretical attenuation model corresponding to the type of base station; and

a received signal strength map generating means for generating a map of signal strength received at each of said at least one receiving point on the basis of said non-environment-affecting theoretical values and said environment affecting factors.

11. The apparatus according to claim 10, wherein the environment affecting obtaining means comprising:

a signal strength input means for inputting the received signal strengths obtained by performing actual measurements at the at least one receiving point; and

an environment affecting factor calculating means for subtracting the at least one non-environment-affecting theoretical value calculated by said non-environment-affecting theoretical attenuation model calculating means for said type of base station, the transmitting point and the receiving point, from the received signal strength obtained by actual measurement, to obtain said environment affecting factor between the transmitting point and the receiving point.

12. The apparatus according to claim 10, further comprising:

an environment factor deducing means for deducing additional unknown environment affecting factors from the obtained environment affecting factors.

13. The apparatus according to claim 10, further comprising:

a mapping means for mapping the generated radio signal strength maps into QoS (Quality of Service) maps.

14. The apparatus according to claim 13, further comprising:

an evaluation means for evaluating the QoS maps of a plurality of setting schemes of base stations in which at least one type of base station is placed at said at least one transmitting point, and

a selection means for selecting an optimal setting scheme of base stations according to the evaluating results.

15. The apparatus according to claim 10, wherein said theoretical attenuation model is related to physical specifications of base stations, said physical specifications of base stations including at least one of the power magnitude of the base station antenna and an opening direction and opening type of the base station antenna when the antenna is a directional antenna.

16. The apparatus according claim 15, wherein

a theoretical attenuation model formula corresponding to an omni-directional antenna is:

P_A(B)[dBm]=C−

Klog(|AB|)

and a theoretical attenuation model formula corresponding to a directional antenna is;

P_A(B)[dBm]=C−

(K₁+θ

K₂)log(|AB|)

where A represents the transmitting point, B represents the receiving point, P_A(B) represents the strength of the radio signal from the transmitting point A received at the receiving point B, |AB| represents the distance between the transmitting point A and the receiving point B, θ

represents the angle between the main axis of the directional antenna and the connecting line from the transmitting point A to the receiving point B, and C, K, K1, K2 are parameters related to physical specifications of the base station.