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WO1996009697A1 - Dispositif pour systeme de radiocommunications a repeteurs - Google Patents

Dispositif pour systeme de radiocommunications a repeteurs Download PDF

Info

Publication number
WO1996009697A1
WO1996009697A1 PCT/SE1995/000998 SE9500998W WO9609697A1 WO 1996009697 A1 WO1996009697 A1 WO 1996009697A1 SE 9500998 W SE9500998 W SE 9500998W WO 9609697 A1 WO9609697 A1 WO 9609697A1
Authority
WO
WIPO (PCT)
Prior art keywords
repeater
previous
message
repeaters
acccording
Prior art date
Application number
PCT/SE1995/000998
Other languages
English (en)
Inventor
Johan Wickman
Original Assignee
Telia Ab
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Telia Ab filed Critical Telia Ab
Priority to EP95932981A priority Critical patent/EP0783805A1/fr
Priority to AU35800/95A priority patent/AU3580095A/en
Publication of WO1996009697A1 publication Critical patent/WO1996009697A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/155—Ground-based stations
    • H04B7/15507—Relay station based processing for cell extension or control of coverage area
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/14—WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Definitions

  • the present invention can be classified among such communication systems that are indicated in the introduction to the subsequent patent claim 1.
  • repeaters or repeater functions in the system are arranged to achieve macro diversity and by that reduce fading and time dispersion.
  • the repeater application can at that be used at radio based local network applications comprising area restricted mobile access.
  • the application implies that the terminating wire connection to the subscriber is replaced by or completed by surface covering radio.
  • the subscriber is offered terminal mobility within one or more restricted areas.
  • the number of base stations be reduced by a factor 10-100, with the result that among other things wire connection of base units can be dramatically reduced.
  • the potential importance of repeaters for DECT is confirmed by heavy accelerating interest within the field. Repeaters can consequently be used for creating radio covering also at high signal attenuation in relation to the dynamics of the system.
  • the repeater functions are obtaining even higher advantages in radio based communication systems than what was previously possible.
  • the invention can also be achieved improved functions regarding repeating principles.
  • the repeaters can at that in their turn solve problems of surface covering for new powerful local network applications such as, for instance, area restricted mobile access.
  • figure 1 in the form of a principal diagram shows example of use of DECT with repeaters for local net replacement with area restricted mobility
  • figure 2 shows example of two adjacent repeaters with overlapping coverage area
  • figuer 3 shows in schematic form macro diversity.
  • Repeaters can, consequently, be used to create radio coverage also at high signal attenuation in relation to the dynamics of the system.
  • the invention entails that repeaters can also be used for creating macro diversity and by that reduce the influence of fading and time dispersion, for mobile and stationary digital radio systems with time shared channel access.
  • Fading consists of variations of the signal strength in time or room due to interference between dfferent paths of propagation and (varying) shadowing.
  • the different propagations paths have different transit times which causes time dispersion.
  • High time dispersion implies risk for intersymbolic interference, unless counteracting measures are taken (channel equalizer, directional antenna, antenna diversity, multi carrier modulation etc) .
  • the time dispersion is often well correlated to the fading.
  • Macro diversity implies that influence of both short (rapid) and long (slow) fading is reduced by continuously selecting the best one of two separated antennas. In this way necessary fading margin can be considerably reduced (often more than 10 dB) . It can be interesting to make a comparison with macro diversity, a technology which is expected to be used generally for DECT. Micro diversity, however, results in that only the short fading can be reduced, consequently not the long fading which is also called shadow fading. Furthermore the micro diversity antennas must be efficiently separated in many outdoor applications. A thing that can bring about more expensive installations.
  • Reduced fading margin implies that the system can offer surface covering with higher transmission quality and capacity at lower costs. Reduced influence from time dispersion implies increased transmission quality i surroundings with extensive multipath propagation.
  • REP signifies repeater in a wireless system with time shared channel access.
  • PP signifies mobile or stationary user unit (portable part in the DECT-standard) , in wireless system with time shared channel access.
  • BAS signifies base station, (radio fixed part in the DECT-standard) , in wireless system with time shared channel access.
  • Adjacent REP with common or partly common coverage area measure signal strength in uplink from one and the same PP.
  • the invention comprises a new, simple protocol for such comparing communication (NB; the protocol can also be used for representing bit error level):
  • the comparing communication can be performed by measured signal level being represented by a message where the length of the message corresponds to the signal level.
  • the message must be long enough to make possible necessary resolution, short enough to make possible a comparison before repeating must be done, and short enough to make it possible for a sufficiently number of PP to be managed by REP. Further, the solution of the message must not be so high that the slight time dispersion which can occur between adjacent PP in wireless communication threatens the correct interpretation of the message.
  • Time dispersion and time delay between REP depends among other things on the distance. For area restricted mobile access is the max. distance between adjacent REP probably 200 m. This makes possible a maximal solution of about 1 ⁇ s. If we choose to represent the signal strength with 20 different intervals, this implies that the length of the message is 20 ⁇ s. Further is needed in all about 10 ⁇ s for start- and finish operations of the message, which results in a total of 30 ⁇ s. This can be compared with the length of a time frame 10 ms, time slot 420 ⁇ s, and guarding period between time slots 56 ⁇ s. The technology can consequently be used for very rapid repeating within a time frame or even between consecutive time frames. At one for both REPs known point of time/channel in relation to PP-channel the message is sent. The message can for instance be sent in a guard-period immediately after the PP time slot which the REP has received.
  • REP starts listening as soon as it is no longer transmitting the message. That REP which finished first will "hear” the other REP. This implies that the REP with least received PP-signal strength will be eliminated and consequently shall not repeat to the base station. That REP which does not "hear” any signal strength message shall, on the contrary, repeat to the base station.
  • REPla and REPIB receive signal from PP.
  • REPla and REPIB compare received signal strength.
  • Ill REP with max PP-signal repeats to BAS.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Système de radiocommunications se présentant sous la forme d'un faisceau hertzien numérique mobile et/ou fixe, utilisant l'accès aux canaux en temps partagé. De plus, une ou plusieurs fonctions répéteur ou un ou plusieurs répéteurs sont agencés comme partie intégrante entre des stations de bases concernées et les terminaux ou les unités mobiles. Les répéteurs cités sont agencés pour obtenir une macro-diversité afin de réduire l'influence des évanouissements et de la dispersion temporelle.
PCT/SE1995/000998 1994-09-21 1995-09-06 Dispositif pour systeme de radiocommunications a repeteurs WO1996009697A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP95932981A EP0783805A1 (fr) 1994-09-21 1995-09-06 Dispositif pour systeme de radiocommunications a repeteurs
AU35800/95A AU3580095A (en) 1994-09-21 1995-09-06 Device at radio base communication system operating with repeaters

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9403161-4 1994-09-21
SE9403161A SE513448C2 (sv) 1994-09-21 1994-09-21 Anordning vid radiobaserat kommunikationssystem som arbetar med repeterare

Publications (1)

Publication Number Publication Date
WO1996009697A1 true WO1996009697A1 (fr) 1996-03-28

Family

ID=20395312

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1995/000998 WO1996009697A1 (fr) 1994-09-21 1995-09-06 Dispositif pour systeme de radiocommunications a repeteurs

Country Status (4)

Country Link
EP (1) EP0783805A1 (fr)
AU (1) AU3580095A (fr)
SE (1) SE513448C2 (fr)
WO (1) WO1996009697A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996022001A3 (fr) * 1995-01-12 1996-09-12 Nokia Telecommunications Oy Repetiteur en mode direct destine a un systeme radio mobile
WO2002078210A3 (fr) * 2001-02-21 2003-04-03 Ericsson Inc Obtention de diversite dans un reseau de communications

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3829777A (en) * 1972-02-10 1974-08-13 Kokusai Denshin Denwa Co Ltd Control system for diversity transmission in a terrestrial station of satellite communication
EP0020893A1 (fr) * 1979-06-08 1981-01-07 Robert Bosch Gmbh Réseau radio

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3829777A (en) * 1972-02-10 1974-08-13 Kokusai Denshin Denwa Co Ltd Control system for diversity transmission in a terrestrial station of satellite communication
EP0020893A1 (fr) * 1979-06-08 1981-01-07 Robert Bosch Gmbh Réseau radio

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996022001A3 (fr) * 1995-01-12 1996-09-12 Nokia Telecommunications Oy Repetiteur en mode direct destine a un systeme radio mobile
US6052557A (en) * 1995-01-12 2000-04-18 Nokia Telecommunication Oy Direct mode repeater in a mobile radio system
WO2002078210A3 (fr) * 2001-02-21 2003-04-03 Ericsson Inc Obtention de diversite dans un reseau de communications
US7113745B2 (en) 2001-02-21 2006-09-26 Ericsson Inc. Method to achieve diversity in a communication network

Also Published As

Publication number Publication date
AU3580095A (en) 1996-04-09
SE9403161L (sv) 1996-03-22
SE9403161D0 (sv) 1994-09-21
EP0783805A1 (fr) 1997-07-16
SE513448C2 (sv) 2000-09-18

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