CA2095489A1 - Spectrum extension protocol for second generation cordless telephone - Google Patents
Spectrum extension protocol for second generation cordless telephoneInfo
- Publication number
- CA2095489A1 CA2095489A1 CA002095489A CA2095489A CA2095489A1 CA 2095489 A1 CA2095489 A1 CA 2095489A1 CA 002095489 A CA002095489 A CA 002095489A CA 2095489 A CA2095489 A CA 2095489A CA 2095489 A1 CA2095489 A1 CA 2095489A1
- Authority
- CA
- Canada
- Prior art keywords
- channel
- scanning
- communication resource
- rss
- predetermined threshold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000001228 spectrum Methods 0.000 title abstract description 12
- 238000000034 method Methods 0.000 claims description 13
- 239000003550 marker Substances 0.000 claims description 3
- 238000013468 resource allocation Methods 0.000 claims 8
- 108091006146 Channels Proteins 0.000 description 38
- 238000010586 diagram Methods 0.000 description 4
- GNENVASJJIUNER-UHFFFAOYSA-N 2,4,6-tricyclohexyloxy-1,3,5,2,4,6-trioxatriborinane Chemical compound C1CCCCC1OB1OB(OC2CCCCC2)OB(OC2CCCCC2)O1 GNENVASJJIUNER-UHFFFAOYSA-N 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
Landscapes
- Mobile Radio Communication Systems (AREA)
Abstract
SPECTRUM EXTENSION PROTOCOL FOR SECOND
GENERATION CORDLESS TELEPHONE
Abstract of the Disclosure A base station (10) includes a scanning receiver (18) for scanning a plurality of channels to measure an RSS level for each channel scanned. The base station includes a computer controller (16) that stores the measured RSS levels to create a table of RSS values. If a link request is received by the base station from a radio telephone handset on a first channel, prior to granting an RF link, the base station determines whether the first channel has an RSS level above a predetermined threshold. If the RSS level of the first channel is above the threshold, the base station re-assigns a second channel, that has an RSS level below the predetermined threshold, to the radio telephone.
GENERATION CORDLESS TELEPHONE
Abstract of the Disclosure A base station (10) includes a scanning receiver (18) for scanning a plurality of channels to measure an RSS level for each channel scanned. The base station includes a computer controller (16) that stores the measured RSS levels to create a table of RSS values. If a link request is received by the base station from a radio telephone handset on a first channel, prior to granting an RF link, the base station determines whether the first channel has an RSS level above a predetermined threshold. If the RSS level of the first channel is above the threshold, the base station re-assigns a second channel, that has an RSS level below the predetermined threshold, to the radio telephone.
Description
20954~9 PATENT APPLICATION
Docket No.: PT01391J
Inventors: Stelios J. Patsiokas Paul D. Marko Craig P. Wadin SPECTRUM EXTENSION PROTOCOL FOR SECOND
GENERATION CORDLESS TELEPHONE
Technlcal F~eld This invention relates generally to communications 15 electronics equipment, and more specitically, to second generation cordless telephones (CT2).
Back~round Present CT2 (or telepoint) systems in accordance with the 20 CT2 Common Air Interface (the regulations governing the CT2 communication systems) have been allocated 4 MHz (864.1-868.1) of spectrum, which provides 40 communications channels spaced at 100kHz intervals. This common band has been allocated across Europe and in several territories in the far east.
25 However, due to capacity limitations in the CT2 Common Air Interface several jurisdictions may increase the portion of the spectrum allocated to CT2 by an additional band or two additional bands at each side of the present CT2 band.
Due to the binary frequency shift keying (BFSK), 30 modulation scheme and filtering (selectivity) limitations, the maximum number of channels that can be used in the same coverage area without degradation in RF coverage and audio quality is 12 to 16.
This limits the capacity of the telepoint network in highly 35 contested areas. The problem is exacerbated when multiple networks and operators are operating in the same area due to synchronization requirements. There is a need, therefor0, to ;
- . ~
Docket No.: PT01391J
Inventors: Stelios J. Patsiokas Paul D. Marko Craig P. Wadin SPECTRUM EXTENSION PROTOCOL FOR SECOND
GENERATION CORDLESS TELEPHONE
Technlcal F~eld This invention relates generally to communications 15 electronics equipment, and more specitically, to second generation cordless telephones (CT2).
Back~round Present CT2 (or telepoint) systems in accordance with the 20 CT2 Common Air Interface (the regulations governing the CT2 communication systems) have been allocated 4 MHz (864.1-868.1) of spectrum, which provides 40 communications channels spaced at 100kHz intervals. This common band has been allocated across Europe and in several territories in the far east.
25 However, due to capacity limitations in the CT2 Common Air Interface several jurisdictions may increase the portion of the spectrum allocated to CT2 by an additional band or two additional bands at each side of the present CT2 band.
Due to the binary frequency shift keying (BFSK), 30 modulation scheme and filtering (selectivity) limitations, the maximum number of channels that can be used in the same coverage area without degradation in RF coverage and audio quality is 12 to 16.
This limits the capacity of the telepoint network in highly 35 contested areas. The problem is exacerbated when multiple networks and operators are operating in the same area due to synchronization requirements. There is a need, therefor0, to ;
- . ~
2~9~
increase the spectrum for CT2 so as to accommodate high traffic requirements in congested areas and minimize interference.
This, however, should be backward and forward compatible with the existing infrastructure.
Conventional telepoint base stations utilize a number of transceiven for the provision of telephone interconnect to subscribers. The base receiver is scanning all forty channels continuously until it detects a seNice request signal from a CT2 handset. After that particular transceiver is occupied with the conversation, another receiver starts scanning all forty channels until it detects service request. It should be noted that the scanning of all channels can also be done simultaneously by several receivers.
Summary of the Inventlon According to the invention, existing hardware of a radio telephone base station remains intact and an additional receiver is added to the base station. The receiver is scanning all channels from both the primary (existing spectrum) and secondary (new spectrum) bands to measure an RSS level for each channel scan. Thus, a look-up table is created at the base station indicating the RSS values of all channels old and new.
The transceivers at the base station are always scanning the primary (old) channels for service requests. However, the existence of the look-up table indicating channel activity enables the redirection of communication to the new spectrum when channel activity on the old spectrum is maximum. If a link request is received by the base station from a cailing radio telephone on a first channel within the primaly band, prior to granting an RF link, the base station determines whether the primary band has an activity level above a first predetermined threshold, based on the measured RSS levels for the primary band. If the activity level of the primary band is above the first predetermined threshold, the base station re-assigns the calling radio telephone, a second clear channel in the secondary band.
`
2~5~9 Brlef Descrletlon of the Drawlngs FIG. 1 is a block diagram of a CT2 base station in accordance with the invention.
FIG. 2 is a flow diagram of a method in accordance with the invention.
petalled Descrlptlon of the Preferred Embodlment Referring to FIG. 1, there is shown a block diagram of a CT2 base station 10 in accordance with the invention. The base station 10 comprises a first transceiver 12 (which comprises a transmitter 20 and a receiver 22) and a second transceiver 14 (which comprises a transmitter 24 and a receiver 26). These transceivers are for communicating with radio telephone handsets. A microcontroller 16 controls the operation of the base station 10. In accordance with the invention, the base station 10 includes a scanning receiver 18 which scans all of the CT2 channels (e.g., 80 channels) five times per scan cycle to sample an RSS level 10r each channel within the CT2 band(s). At the end of the five scans, the microcontroller 16 stores the highest of the five RSS samples for each channel in its memory (or in an extemai memory 17 coupled to the microcontroller 16). The stored RSS levels are used to determine the activity level in the band(s) scanned.
This invention accommodates CT2 operation over an eight MHz bandwidth without having to replace infrastructure which is ;
already installed in the field. The introduction of the new scanning receiver 18 and an appropriate software algorithm make it possible. Specifically the additional receiver 18 continuously scans all 80 channels as follows:
rlme/Channel: 2.5 ms Total scan time: (2.5 ms/channel) (80 channels) (5 samples) +
10ms=1010ms . . -.
.
: ~ , , 209~89 The RSS values for all channels are continuously updated and a look-up table is being created. The table is then used to determine activity levels for the subject band(s).
When a handset initiates a call, the base station 10 responds to it following standard CAI protocol within the primary, 4 MHz frequency, band. This is done via one of the transceivers 12 or 14. However, prior to enabling voice communications on the selected primary band (or on the channel selected by the handset), the base controller 16 checks the updated RSS levels of the primary band (or of the selected channel). This is done from the look-up table which is continuously updated by the scanning receiver 18. If the RSS activity level of this band (or channel) is below a predetermined threshold, the base enables voice communications on the primary band (or on the selected channel), otherwise it initiates a link re-establishment command directing the handset to select another (clear) channel. This predetermined threshold is selected to correspond to a maximum level of energy (e.g., interference from other channels) determined to be acceptable for quality voice communication.
The determination of whether the channel selected by the handset is suitable for enablement of a voice communication may be made either on the basis of the RSS level in the selected channel or on the RSS activity level of the band in which the selected channel is located.
Since the scanning receiver 18 updates the look-up table continuously, the base station controller 16 could immediately grant a link and enable voice communications as long as it detects a service request on a predetermined interval of spectrum that does not experience interference. This means that when the priority spectrum of 4 MHz is clean (i.e., not congested), the end-user would acquire service without the delays of link re-establishment.
Referring to FIG 2, there is shown is a flow diagram of a method in accordance with the invention. When a link request is received from a calling radio telephone handset, in decision 100 the base controller determines whether a channel marker pattern ~ 8 ~ 9 (CHMP), or link request, is present on channel X. If decision 100 is negative, in step 102 the base transceiver continues scanning all 40 channels of the present CT2 spectnum (i.e., the primary band). If deàsion 100 is affirmative, the process continues to 5 decision 104. In decision 104 it is determined whether channel X
is included in a set of optimum channels (e.g., those having an RSS level below a predetermined threshold). If decision 104 is affirmative, the base grants the calling handset a link on channel X. If decision 104 is negative, in step 108 the base sends a link 10 re-establishment command to the calling handset to send another link request on a clear channel Y. Channe~l Y has been determined from the look-up table to be clear by its RSS level (e.g., it is below a predetermined threshold). Therefore, the benefits of an extended CT2 band can be enjoyed without 15 requiring that all handsets include the capability to operate on the extended band.
increase the spectrum for CT2 so as to accommodate high traffic requirements in congested areas and minimize interference.
This, however, should be backward and forward compatible with the existing infrastructure.
Conventional telepoint base stations utilize a number of transceiven for the provision of telephone interconnect to subscribers. The base receiver is scanning all forty channels continuously until it detects a seNice request signal from a CT2 handset. After that particular transceiver is occupied with the conversation, another receiver starts scanning all forty channels until it detects service request. It should be noted that the scanning of all channels can also be done simultaneously by several receivers.
Summary of the Inventlon According to the invention, existing hardware of a radio telephone base station remains intact and an additional receiver is added to the base station. The receiver is scanning all channels from both the primary (existing spectrum) and secondary (new spectrum) bands to measure an RSS level for each channel scan. Thus, a look-up table is created at the base station indicating the RSS values of all channels old and new.
The transceivers at the base station are always scanning the primary (old) channels for service requests. However, the existence of the look-up table indicating channel activity enables the redirection of communication to the new spectrum when channel activity on the old spectrum is maximum. If a link request is received by the base station from a cailing radio telephone on a first channel within the primaly band, prior to granting an RF link, the base station determines whether the primary band has an activity level above a first predetermined threshold, based on the measured RSS levels for the primary band. If the activity level of the primary band is above the first predetermined threshold, the base station re-assigns the calling radio telephone, a second clear channel in the secondary band.
`
2~5~9 Brlef Descrletlon of the Drawlngs FIG. 1 is a block diagram of a CT2 base station in accordance with the invention.
FIG. 2 is a flow diagram of a method in accordance with the invention.
petalled Descrlptlon of the Preferred Embodlment Referring to FIG. 1, there is shown a block diagram of a CT2 base station 10 in accordance with the invention. The base station 10 comprises a first transceiver 12 (which comprises a transmitter 20 and a receiver 22) and a second transceiver 14 (which comprises a transmitter 24 and a receiver 26). These transceivers are for communicating with radio telephone handsets. A microcontroller 16 controls the operation of the base station 10. In accordance with the invention, the base station 10 includes a scanning receiver 18 which scans all of the CT2 channels (e.g., 80 channels) five times per scan cycle to sample an RSS level 10r each channel within the CT2 band(s). At the end of the five scans, the microcontroller 16 stores the highest of the five RSS samples for each channel in its memory (or in an extemai memory 17 coupled to the microcontroller 16). The stored RSS levels are used to determine the activity level in the band(s) scanned.
This invention accommodates CT2 operation over an eight MHz bandwidth without having to replace infrastructure which is ;
already installed in the field. The introduction of the new scanning receiver 18 and an appropriate software algorithm make it possible. Specifically the additional receiver 18 continuously scans all 80 channels as follows:
rlme/Channel: 2.5 ms Total scan time: (2.5 ms/channel) (80 channels) (5 samples) +
10ms=1010ms . . -.
.
: ~ , , 209~89 The RSS values for all channels are continuously updated and a look-up table is being created. The table is then used to determine activity levels for the subject band(s).
When a handset initiates a call, the base station 10 responds to it following standard CAI protocol within the primary, 4 MHz frequency, band. This is done via one of the transceivers 12 or 14. However, prior to enabling voice communications on the selected primary band (or on the channel selected by the handset), the base controller 16 checks the updated RSS levels of the primary band (or of the selected channel). This is done from the look-up table which is continuously updated by the scanning receiver 18. If the RSS activity level of this band (or channel) is below a predetermined threshold, the base enables voice communications on the primary band (or on the selected channel), otherwise it initiates a link re-establishment command directing the handset to select another (clear) channel. This predetermined threshold is selected to correspond to a maximum level of energy (e.g., interference from other channels) determined to be acceptable for quality voice communication.
The determination of whether the channel selected by the handset is suitable for enablement of a voice communication may be made either on the basis of the RSS level in the selected channel or on the RSS activity level of the band in which the selected channel is located.
Since the scanning receiver 18 updates the look-up table continuously, the base station controller 16 could immediately grant a link and enable voice communications as long as it detects a service request on a predetermined interval of spectrum that does not experience interference. This means that when the priority spectrum of 4 MHz is clean (i.e., not congested), the end-user would acquire service without the delays of link re-establishment.
Referring to FIG 2, there is shown is a flow diagram of a method in accordance with the invention. When a link request is received from a calling radio telephone handset, in decision 100 the base controller determines whether a channel marker pattern ~ 8 ~ 9 (CHMP), or link request, is present on channel X. If decision 100 is negative, in step 102 the base transceiver continues scanning all 40 channels of the present CT2 spectnum (i.e., the primary band). If deàsion 100 is affirmative, the process continues to 5 decision 104. In decision 104 it is determined whether channel X
is included in a set of optimum channels (e.g., those having an RSS level below a predetermined threshold). If decision 104 is affirmative, the base grants the calling handset a link on channel X. If decision 104 is negative, in step 108 the base sends a link 10 re-establishment command to the calling handset to send another link request on a clear channel Y. Channe~l Y has been determined from the look-up table to be clear by its RSS level (e.g., it is below a predetermined threshold). Therefore, the benefits of an extended CT2 band can be enjoyed without 15 requiring that all handsets include the capability to operate on the extended band.
Claims (15)
1. A radio communication resource allocation device comprising:
a transceiver for receiving communication resource requests from radio telephones and for transmitting communication resource allocation signals to the radio telephones;
a scanning receiver for scanning a plurality of channels to measure an RSS level for each channel scanned; and a controller, coupled to the scanning receiver and to the transceiver, for storing the measured RSS levels to create a table of RSS values, the controller comprising:
means for determining whether a communication resource request is on a channel having an RSS level above a predetermined threshold; and means for causing the transceiver to transmit a communication resource re-establishment request when communication resource request is on a channel having an RSS
level above the predetermined threshold, the communication resource re-establishment request being transmitted on a channel having an RSS level that is below the predetermined threshold.
a transceiver for receiving communication resource requests from radio telephones and for transmitting communication resource allocation signals to the radio telephones;
a scanning receiver for scanning a plurality of channels to measure an RSS level for each channel scanned; and a controller, coupled to the scanning receiver and to the transceiver, for storing the measured RSS levels to create a table of RSS values, the controller comprising:
means for determining whether a communication resource request is on a channel having an RSS level above a predetermined threshold; and means for causing the transceiver to transmit a communication resource re-establishment request when communication resource request is on a channel having an RSS
level above the predetermined threshold, the communication resource re-establishment request being transmitted on a channel having an RSS level that is below the predetermined threshold.
2. The radio communication resource allocation device of claim 1 wherein the scanning receiver scans the plurality of channels five times per scanning cycle.
3. The radio communication resource allocation device of claim 1 wherein the scanning receiver comprises a scanning period of 1010 milliseconds.
4. The radio communication resource allocation device of claim 3 wherein the scanning receiver scans eighty channels, spaced at 100 KILOHERTZ, each cycle.
5. The radio communication resource allocation device of claim 3 wherein the eighty channels are spaced at 100 KILOHERTZ within the radio band comprising 864 to 868 MEGAHERTZ.
6. In a radio communication system comprising a base station, having a scanning receiver, and a plurality of radio handsets, a communication resource allocation method comprising the steps of:
scanning a plurality of channels with the base station to measure an RSS level for each channel scanned;
storing the measured RSS levels to create a table of RSS
values;
receiving a communication resource request by the base station from a radio handset on a first channel in a primary band;
determining whether the communication resource request was received on a channel having a channel marker pattern;
determining whether the primary band has an RSS activity level above a first predetermined threshold, when it is determined that the communication resource request was received on a channel having a channel marker pattern; and sending a link re-establishment command to the calling radio handset instructing the calling handset to transmit another communication resource request on a second channel, when it is determined that the primary band has an RSS level above the first predetermined threshold, the second channel having an RSS
level below a second predetermined threshold.
scanning a plurality of channels with the base station to measure an RSS level for each channel scanned;
storing the measured RSS levels to create a table of RSS
values;
receiving a communication resource request by the base station from a radio handset on a first channel in a primary band;
determining whether the communication resource request was received on a channel having a channel marker pattern;
determining whether the primary band has an RSS activity level above a first predetermined threshold, when it is determined that the communication resource request was received on a channel having a channel marker pattern; and sending a link re-establishment command to the calling radio handset instructing the calling handset to transmit another communication resource request on a second channel, when it is determined that the primary band has an RSS level above the first predetermined threshold, the second channel having an RSS
level below a second predetermined threshold.
7. The method of claim 6 wherein the first predetermined threshold is equal to the second predetermined threshold.
8. The method of claim 6 wherein the scanning step comprises scanning the plurality of channels five times per scanning cycle.
9. The method of claim 8 wherein the scanning step comprises scanning at a period of 1010 milliseconds.
10. The method of claim 9 wherein the scanning step comprises scanning eighty channels, spaced at 100 KILOHERTZ, each cycle.
11. The method of claim 10 wherein the eighty channels are spaced at 100 KILOHERTZ within the radio band comprising 864 to 868 MEGAHERTZ.
12. In a radio communication system comprising a base station, having a scanning receiver, and a plurality of radio handsets, a communication resource allocation method comprising the steps of:
scanning a plurality of channels with the base station to measure an RSS level for each channel scanned;
storing the measured RSS levels to create a table of RSS
values;
receiving a communication resource request by the base station from a radio handset on a first channel;
determining whether the communication resource request was received on a channel having an RSS level above a first predetermined threshold; and sending a link re-establishment command to the calling handset instructing the calling handset to transmit another communication resource request on a second channel, when it is determined that the communication resource request was received on a channel having an RSS level above the first predetermined threshold, the second channel having an RSS
level below a second predetermined threshold.
scanning a plurality of channels with the base station to measure an RSS level for each channel scanned;
storing the measured RSS levels to create a table of RSS
values;
receiving a communication resource request by the base station from a radio handset on a first channel;
determining whether the communication resource request was received on a channel having an RSS level above a first predetermined threshold; and sending a link re-establishment command to the calling handset instructing the calling handset to transmit another communication resource request on a second channel, when it is determined that the communication resource request was received on a channel having an RSS level above the first predetermined threshold, the second channel having an RSS
level below a second predetermined threshold.
13. The method of claim 12 wherein the first predetermined threshold is equal to the second predetermined threshold.
14. The method of claim 12 wherein the scanning step comprises scanning the plurality of channels five times per scanning cycle.
15. The method of claim 12 wherein the scanning step comprises scanning at a period of 1010 milliseconds.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US87943892A | 1992-05-06 | 1992-05-06 | |
| US07/879,438 | 1992-05-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2095489A1 true CA2095489A1 (en) | 1993-11-07 |
Family
ID=25374160
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002095489A Abandoned CA2095489A1 (en) | 1992-05-06 | 1993-05-04 | Spectrum extension protocol for second generation cordless telephone |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2095489A1 (en) |
-
1993
- 1993-05-04 CA CA002095489A patent/CA2095489A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |