SE514663C2

SE514663C2 - Mobile Telecommunications System

Info

Publication number: SE514663C2
Application number: SE9802387A
Authority: SE
Inventors: Per-Goeran Andermo; Anders Oesterberg
Original assignee: Radio Design Innovation Tj Ab
Priority date: 1998-07-03
Filing date: 1998-07-03
Publication date: 2001-04-02
Also published as: AU4949199A; SE9802387D0; SE9802387L; EP1095531A1; IL140662A0; WO2000002405A1

Abstract

The invention relates to a method and an arrangement in a mobile telecommunication system using lobes for establishing and maintaining a radio channel between a mobile station and a base station. The base station measures received signal strength or signal quality in each lobe in a sector by means of a Direction Finding Unit (DFU). The DFU selects the lobe with the highest received signal strength or signal quality and connects the transceiver equipment of the base station to the mobile station using the selected lobe.

Description

514 663 2 DFU Riktningssökarenhet (Direction Finding Unit) MS Mobilstation MTX Mobiltelefonväxel BSC Basstationstyrenhet (Base Site Controller) för styrning av LSU och DFU BS Basstation TRX Sändar-/mottagarutrustning (Transmitter/Receiver Equipment) CC Anropskanal (Calling Channel) TCfree Ledig traﬁkkanal TCho Traﬁkkanal som mottar handover från en annan kanal RSS Radiosignalstyrka RS SI Radiosignalstyrkeindikator LSU Lobfommingsenhet (Lobe Shaping Unit) SSM Signalstyrkemätning SR Signalstyrkemottagare eller TRX som används for singnalstyrkemätningar Förutom konventionell utrustning som t ex sändar-/mottaganitrustning (TRX), antennanordningar, styranordningar för att upprätta kanaler, anordningar för att mäta signalstyrka kopplade till övervakningsanordningar for handoverbeslut, inbegriper basstationen (BS) enligt föreliggande uppfinning också en riktnings- sökarenhet (DFU) och lobformningsenheter (LSU). RSSI-registren, RSSI och snabbscanningsomkopplaren i figur l utgör DFU. Mobiltelefonväxeln MTX utgör gränssnittet till det fasta publika eller privata nätet, t ex vanlig telefoni (POTS, ISDN). Mobiltelefonväxeln MTX anses vara den mest komplexa delen av mobil- kommunikationssystemet och alla slutliga beslut avseende handover, roaming, samtalsuppkoppling, osv, kommer ﬁån MTX. TRX-utrustningen är kopplad till en lobforrnningsenhet (LSU) som i sin tur är kopplad till en gruppantenn. Lobfonn- ningsenheten (LSU) är anordnad att bilda lober med olika bredder och förstärk- ningar i godtyckliga riktningar både i upplänken och nedlänken genom att ändra fas- och amplitudkoeﬁicienter. Lobfornmingsenheten beskrivs i detalj i patent- ansökningar, överlåtna till Radio Design Innovation TJ AB, vilka ansökningar införlivas härmed genom hänvisning. 514 663 2 DFU Direction Finding Unit MS Mobile Station MTX Mobile Phone Switch BSC Base Station Controller for LSU and DFU BS Base Station TRX Transmitter / Receiver Equipment CC Calling TC Hook Channel Traction channel that receives handover from another channel RSS Radio signal strength RS SI Radio signal strength indicator LSU Lobe Shaping Unit SSM Signal strength measurement SR Signal strength receiver or TRX used for signal strength measurements In addition to conventional equipment such as transceivers (transmissions) channels, devices for measuring signal strength coupled to monitoring devices for handover decisions, the base station (BS) according to the present invention also includes a direction finder unit (DFU) and lobe forming units (LSU). The RSSI registers, RSSI and the fast scan switch in Figure 1 constitute DFU. The MTX mobile telephone exchange forms the interface to the fixed public or private network, eg ordinary telephony (POTS, ISDN). The MTX mobile telephone exchange is considered to be the most complex part of the mobile communication system and all final decisions regarding handover, roaming, call set-up, etc., come from MTX. The TRX equipment is connected to a beamforming unit (LSU) which in turn is connected to a group antenna. The lobe forming unit (LSU) is arranged to form lobes with different widths and reinforcements in arbitrary directions in both the uplink and the downlink by changing the phase and amplitude coefficients. The lobbying unit is described in detail in patent applications, transferred to Radio Design Innovation TJ AB, which applications are hereby incorporated by reference.

Om vi nu återgår till riktningssökarenheten DFU är det dess ansvar att lokalisera en mobilstation (MS) så snabbt som möjligt for att undvika att signaler- ingen mellan mobiltelefonväxeln och mobilstationen tappas. Denna funktion krävs speciellt under samtalsuppkoppling eller handoversituationer när mobilstationens 10 20 25 30 35 514 663 3 lägeinitialt är okänt for basstationstyrenheten BSC. Ovannämnda lokalisering åstadkommes genom att allokera smala antennlober (genom att använda lobform- ningsenheten och gruppantennen) som täcker hela arean inuti en sektor. Riktnings- sökarenheten DFU scannar alla mottagningslober samtidigt eller företrädesvis i en följd. Vid detektering av en mottagen signalstyrka i en eller ﬂera mottagningslober väljs loben med högst signalstyrka och basstationstyrenheten BSC upprättar en konfigurerad lob i riktning av den valda loben för kommunikation mellan mobil- stationen och en TRX. Man skall naturligtvis inse att mobilstationen MS måste identiﬁera basstationen innan den sänder signaler till basstationen. Detta åstad- kommes genom att basstationen sänder identiﬁkationssignaler i en bred lob för att informera MS, som täcks av nämnda breda lob, om sin existens.If we now return to the direction finder unit DFU, it is its responsibility to locate a mobile station (MS) as quickly as possible in order to avoid the signaling between the mobile telephone exchange and the mobile station being lost. This function is especially required during call set-up or hand-over situations when the location of the mobile station 10 is initially unknown to the base station controller BSC. The above location is achieved by allocating narrow antenna lobes (using the lobe forming unit and the group antenna) that cover the entire area within a sector. The direction finder unit DFU scans all reception lobes simultaneously or preferably in a sequence. When detecting a received signal strength in one or ﬂ your reception lobes, the lobe with the highest signal strength is selected and the base station controller BSC establishes a configured lobe in the direction of the selected lobe for communication between the mobile station and a TRX. It should of course be understood that the mobile station MS must identify the base station before transmitting signals to the base station. This is achieved by the base station transmitting identification signals in a wide lobe to inform the MS, which is covered by said wide lobe, of its existence.

Ett funktionsprocedurschema för riktningssökarenheten DFU beskrivs nedan. l. Då basstationstyrenheten mottar en CC-, TCfree- eller TCho-aktiveringsorder (MTX sänder order till en TRX-enhet), aktiverar BSC riktningssökarenheten DFU och denna inställs på rätt kanalnummer och övervakar den mottagna signalen. En bred lob i lobformningsenheten LSU kopplas till sändaren. 2. Mobilstationen MS aktiverar sin sändare: som reaktion på en sökning; för att upprätta ett MS-initierat samtal; eller på en ny frekvens efter en handoverorder. Effekten börjar ökas och innan ramdata sänds måste riktningssökarenheten DFU ha identifierat loben med den starkaste RF-nivån (radiofrekvens). Basstationstyrenheten BSC upprättar en väg genom utrustningen med den valda loben kopplad till mottagaren. 3. Under mottagning av NMT-ramar mäter riktningssökarenheten DF U RSS och håller ett register för varje lob. BSC läser RS SI-registren från riktnings- sökarenheten DF U och kopplar kontinuerligt den bästa loben till mottagaren. 4. Vid en lärnplig punkt i si gnaleringsschemat läser basstationstyrenheten BSC RSSI-registret från riktningssökarenheten DFU och bestämmer vilken lob som är bäst att använda för sändardelen och kopplar den bästa loben i denna riktning till sändaren, dvs den breda loben transformeras till en smal lob. 5. Under si gnaleringen och talomvandlingen mäter riktningssökarenheten DFU RS SI och basstationstyrenheten BSC kopplar kontinuerligt den bästa loben till mottagare och sändare.A functional procedure diagram for the direction finder unit DFU is described below. l. When the base station controller receives a CC, TCfree or TCho activation command (MTX sends orders to a TRX unit), the BSC activates the direction finder unit DFU and this is set to the correct channel number and monitors the received signal. A wide beam in the beam forming unit LSU is connected to the transmitter. The mobile station MS activates its transmitter: in response to a search; to establish an MS-initiated call; or on a new frequency after a handoverorder. The power starts to increase and before frame data is transmitted, the direction finder unit DFU must have identified the beam with the strongest RF level (radio frequency). The base station controller BSC establishes a path through the equipment with the selected lobe connected to the receiver. 3. When receiving NMT frames, the direction finder unit DF measures U RSS and keeps a register for each lobe. The BSC reads the RS SI registers from the direction finder unit DF U and continuously connects the best beam to the receiver. 4. At a learning point in the signaling scheme, the base station controller BSC reads the RSSI register from the direction finder unit DFU and decides which lobe is best to use for the transmitter part and connects the best lobe in this direction to the transmitter, ie the wide lobe is transformed into a narrow lobe. 5. During signaling and voice conversion, the direction finder unit DFU measures the RS SI and the base station controller BSC continuously connects the best beam to the receiver and transmitter.

En metod som liknar ovannämnda används för signalstyrkemätningar. Det är 10 15 20 25 30 35 514 663 4 SSM-ﬁmktionens ansvar att koppla en SR-enhet (eller kanalenhet) till den bästa loben så att signalstyrkemätningar kan utföras av SR-enheten på den bästa loben.A method similar to the above is used for signal strength measurements. It is the responsibility of the SSM function to connect an SR unit (or channel unit) to the best lobe so that signal strength measurements can be performed by the SR unit on the best lobe.

RS SI-mätningarna initieras från mobiltelefonväxeln MTX.The RS SI measurements are initiated from the MTX mobile telephone exchange.

SSM-funktionen använder samma hårdvarukonfiguration som DFU- funktionen.The SSM function uses the same hardware configuration as the DFU function.

Ett ﬁmktionsschema för SSM-funktionen beskrivs nedan. l. Då basstationstyrenheten mottar en mätaktiveringsorder (MTX sänder order till en TRX- eller SR-enhet) aktiverar basstationstyrenheten riktningssökar- enheten DFU och denna inställs på korrekt kanalnummer och övervakar den mottagna signalen. 2. Riktningssökarenheten identifierar loben med den starkaste RF-nivån. Bas- stationstyrenheten BSC upprättar en väg genom utrustningen med den valda loben kopplad till SR-enheten. 3. SR-enheten utför RSSI- och cb-tomnätningar. l t ex NMT (Nordic Mobile Telephone) kontrolleras ett samtals kvalitet med en styrsignal (rf-ton), dvs en av fyra toner kring 4 kHz. Basstationen sänder o-signalen till mobilstationen som returnerar signalen till basstationen. Kvaliteten hos den retumerade cb- signalen mäts i basstationen och om kvaliteten ligger under ett förutbestämt värde sänder basstationen ett alarm till en MTX. Sedan beordrar MTX basstationen och de omgivande basstationerna att mäta styrkan hos radio- signalen från mobilstationen. Basstationema sänder mätresultaten till MTX varefter MTX kopplar samtalet till basstationen med den högsta mottagna signalstyrkan. 4. Riktningssökarenheten DFU övervakar den mottagna signalen och bas- stationstyrenheten BSC kopplar kontinuerligt den bästa loben till SR-enheten.An operation diagram for the SSM function is described below. l. When the base station controller receives a measurement enable command (MTX sends orders to a TRX or SR unit), the base station controller activates the direction finder unit DFU and this is set to the correct channel number and monitors the received signal. The direction finder unit identifies the beam with the strongest RF level. The base station control unit BSC establishes a path through the equipment with the selected lobe connected to the SR unit. 3. The SR unit performs RSSI and cb empty networks. For example, NMT (Nordic Mobile Telephone) controls the quality of a call with a control signal (rf tone), ie one of four tones around 4 kHz. The base station sends the o-signal to the mobile station which returns the signal to the base station. The quality of the retrieved cb signal is measured in the base station and if the quality is below a predetermined value, the base station sends an alarm to an MTX. Then the MTX base station and the surrounding base stations order to measure the strength of the radio signal from the mobile station. The base stations send the measurement results to MTX, after which MTX connects the call to the base station with the highest received signal strength. 4. The direction finder unit DFU monitors the received signal and the base station controller BSC continuously connects the best beam to the SR unit.

Då TX-enheten är klar kopplar BSC bort SR-utrustningen.When the TX unit is ready, the BSC disconnects the SR equipment.

Det inses av fackmän på området att föreliggande uppfinning kan realiseras i andra speciﬁka former utan att gå ur ramen eller de väsentliga egenskapema hos uppﬁnningen. De för närvarande beskrivna utföringsforrnerna skall följaktligen i alla hänseenden anses vara illustrativa och inte begränsande. Omfattningen av uppﬁnningarna, som indikeras av de bifogade patentkraven snarare än av den före- gående beskrivningen, och alla modifikationer som faller innanför betydelsen och ekvivalensbredden därav avses omfattas av dessa.It will be appreciated by those skilled in the art that the present invention may be embodied in other specific forms without departing from the scope or essential characteristics of the invention. Accordingly, the presently described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the inventions, which are indicated by the appended claims rather than by the foregoing description, and all modifications that fall within the meaning and breadth of equivalence thereof are intended to be embraced therein.

Claims

10 15 20 25 30 35 514 663 5 PATENT REQUIREMENTS

A method in a mobile telecommunication system using lobes to establish a radio channel between a mobile station (MS) and a base station (BS), characterized by the steps of: connecting the base station's transmitters to a wide lobe in a sector; connecting the base station receivers to narrow lobes in the sector via a fast-scanning switch; measuring signal strength (RSS) or signal quality received from the mobile station in each narrow lobe in the sector during the increase in power in the mobile station at the beginning of the frame; selecting the narrow lobe with the highest received signal strength (RSS) or signal quality; coupling the receiving equipment of the base station (BS) to the selected narrow lobe before frame data begins to be transmitted; and coupling the transmitter equipment of the base station (BS) from wide to narrow lobe at the appropriate time in the signaling.

Method according to claim 1, characterized in that the base station (BS) measures the received signal strength (RSS) or the signal quality of narrow lobes in the sector simultaneously or sequentially.

Method according to claim 1 or 2, characterized in that a direction finder unit (DFU) in the base station (BS) measures the received signal strength (RSS) or signal quality in each lobe in the sector and stores the values of the received signal strength or signal quality for each lobe in a memory (RSS1 register).

Method according to claim 3, characterized in that a base station controller (BSC) reads the values in the memory (RSS1 registers) and determines which beam has the highest received signal strength or signal quality and selects this beam direction for communication with the mobile station.

Method according to claim 4, characterized in that the base station controller (BSC) configures a lobe forming unit (LSU) to establish a preferred lobe, eg narrower lobe, in the direction of the selected lobe towards the mobile station for the respective downlink and / or uplink.

Method according to one of the preceding claims, characterized in that it is used for call connection and / or for handover between sectors.

Method according to one of the preceding claims, characterized in that lobes with different widths and reinforcements in arbitrary directions in both the uplink and the downlink are formed by changing the phase and amplitude coefficients.

Method according to claim 7, characterized in that the base station (BS) sends identification signals in a wide lobe to inform the mobile station (MS), which is covered by said wide lobe, of its existence. 10 20 25 30 35 514 663 b

Method in a mobile telecommunication system using lobes to measure the signal quality of a radio channel between a mobile station (MS) and a base station (BS), characterized by the steps of: connecting the base station receivers to narrow lobes in the sector via a fast scanning switch; measuring signal strength (RSS) or signal quality received from the mobile station in each narrow lobe in the sector; selecting the narrow lobe with the highest received signal strength (RSS) or signal quality; to connect a signal quality receiver unit (SR) to the selected narrow lobe.

Method according to claim 9, characterized in that the signal quality receiver unit (SR) performs signal strength measurements or o-tone measurements in this selected lobe for manual purposes.

Method according to claim 10, characterized in that the base station (BS) monitors the received signal and continuously connects the best beam to the signal quality receiver unit (SR).

Method according to claim 9, 10 or 1, characterized in that the base station (BS) measures the received signal strength (RSS) or the signal quality of narrow lobes in the sector simultaneously or sequentially.

Method according to one of Claims 9 to 12, characterized in that a direction finder unit (DFU) in the base station (BS) measures the received signal strength (RSS) or the signal quality in each lobe in the sector and stores the values of the received signal strength or the signal quality for each lob in a memory (RSSI register).

Method according to claim 13, characterized in that a base station control unit (BSC) reads the values in the memory (RSS1 registers) and determines which beam has the highest received signal strength or signal quality and selects this beam direction for communication with the mobile station.

Method according to claim 14, characterized in that the base station control unit (BSC) configures a lobe forming unit (LSU) to establish a preferred lobe, for example narrower lobe. in the direction of the selected lobe towards the mobile station for the respective downlink and / or uplink.

Method according to one of Claims 9 to 15, characterized in that lobes with different widths and reinforcements in arbitrary directions in both the uplink and the downlink are formed by changing the phase and amplitude coefficients.

Arrangement in a mobile telecommunication system using lobes to establish a radio channel between a mobile station (MS) and a base station (BS), characterized in that a lobe forming unit is arranged to connect the base station's transmitter to a wide lobe in a sector and to connect The base station receiver to narrow lobes in the sector via a fast scanning switch, that a direction finder unit (DFU) in the base station (BS) is arranged to measure signal strength (RSS) or signal quality received from the mobile station each narrow lobe in the sector while increasing the power in the mobile station, to select the narrow beam with the highest received signal strength or signal quality, to connect the receiver part of any TRX equipment in the base station (BS) to the selected narrow beam before frame data starts to be transmitted and to connect the transmitter part of any TRX equipment in the base station (BS) n from wide to narrow lobe using the selected narrow lobe at the appropriate time in signal eringen.

Arrangement in a mobile telecommunication system using lobes to measure the signal quality of a radio channel between a mobile station (MS) and a base station (BS), characterized in that a lobe forming unit is arranged to connect the base station receivers to narrow lobes in the sector via a fast scanning switch, that a direction finder unit (DFU) in the base station (BS) is arranged to measure the signal strength received from the mobile station (RSS) or the signal quality of each narrow beam in the sector, to select the narrow beam with the highest received signal strength or signal quality and to connect a signal quality receiver unit ( SR) to the selected narrow lobe.

Arrangement according to claim 17 or 18, characterized in that the direction finder unit (DFU) comprises an RS SI register, an RSSI unit and said quick scan switch.

Arrangement according to claim 19, characterized in that the direction finder unit (DFU) reads RSSI and keeps an RSSI register for each lobe.

Arrangement according to Claim 19 or 20, characterized in that the base station controller (BSC) reads the RS SI register of the direction finder unit (DFU) and continuously connects the best beam to the receiver.