Method of reducing dead zones within a UMTS system, corresponding mobile telecommunication system and mobile station

• US 20040097223A1
• Filed: 11/07/2003
• Published: 05/20/2004
• Est. Priority Date: 11/08/2002
• Status: Abandoned Application

• Current Assignee: Melco Mobile Communications Europe
• Original Assignee: Melco Mobile Communications Europe
• Inventors: Voyer, Nicolas, Belaiche, Vincent Antoine Victor, Bellec, Martial
• Application Number:
  US10/702,964
• Publication Number:
  US 20040097223A1
• Time in Patent Office: Days
• US Class Current: 455/422.1
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data

Abstract

The present invention relates to a method and a system for reducing the dead zones within a third generation mobile telecommunication system (UMTS). When a mobile station (MS) communicating with a service base station (BS₁) generates a dead zone on at least one uplink of a next base station (BS₂), criteria are determined, according to the invention, based on parameters regarding the uplink and/or downlink between the mobile station (MS) and the base station (BS₁) which, if they are not complied with for the uplink and/or downlink, trigger a radio link interruption in the mobile station (MS). When the power transmitted on the uplink becomes zero, the degradation in the radio coverage of the cell associated with the next base station (BS₂) due to the mobile station (MS) disappears.

Claims

1. ) Method of reducing at least one dead zone relative to a first base station (BS₁) and/or at least one second base station (BS₂), said at least one second base station being next to said first base station (BS₁),

characterized in that, when a first mobile station (ms), currently communicating on at least one first frequency (f_1-UL) with said first base station (BS₁), approaches said second base station (BS₂), at least one other mobile station (MS′

), referred to as a second mobile station, communicating with said second base station (BS₂) on at least one second frequency (f_2-UL), said method comprises the following steps of;

estimation, by said first mobile station (MS), of at least one first (Q_f1) and/or one second (Q_f2) parameters, said first parameter (Q_f1) being representative of the quality of reception of the signals transmitted by said first base station (BS₁) and received by said first mobile station (MS) on a third frequency (f_1-DL), said second parameter (Q_f2) being representative of the quality of reception of the signals transmitted by said second base station (BS₂) and received by said first mobile station (MS) on a fourth frequency (f_2-DL),

determination, at least by said first mobile station (MS), of a third parameter (Q<sub>f1—

dB</sub>-Q<sub>f2—

dB</sub>), said third parameter being dependent on said at least one first (Q_f1) estimated parameter and/or one second (Q_f2) estimated parameter,

comparison of the value of said third determined parameter with a predetermined first threshold value (T<sub>target—

UL</sub>), said first threshold value being representative of a dead zone on the uplink between said second mobile station (MS′

) and said second base station (BS₂) for at least said second frequency (f_2-UL), said dead zone being referred to as an uplink dead zone, said uplink dead zone relating to said at least one second base station (BS₂), and/or

comparison of the value of said third determined parameter with a predetermined second threshold value (T<sub>target—

DL</sub>), said second threshold value being representative of a dead zone on the downlink between said first base station (BS₁) and said first mobile station (MS) for at least said third frequency (f_1-DL), said dead zone being referred to as a downlink dead zone, said downlink dead zone relating to at least said first base station (BS₁), and,

if the value of said third parameter (Q<sub>f1—

dB</sub>-Q<sub>f2—

dB</sub>) exceeds said first threshold value (T<sub>target—

UL</sub>) and/or said second threshold value (T<sub>target—

DL</sub>), said first mobile station interrupts the radio link implemented on at least said first frequency (f_1-UL) and/or said third frequency (f_1-DL) between said first mobile station (MS) and said first base station (BS₁).

2. ) Method according to claim 1, characterized in that said first (Q_f1) and second (Q_f2) estimated parameters are expressed according to one and the same type of measurement, said type of measurement belonging to the group comprising:

a measurement specific (CPICH-Ec/No) to a predetermined first physical channel (CPICH) of the mean energy received per chip, divided by the power spectral density of the interference received in a corresponding radio band, referred to as a first measurement (CPICH-Ec/No);

a measurement (CPICH-RSCP) specific to said predetermined first physical channel (CPICH) of the power of the signal received for a predetermined code of said first physical channel (CPICH), referred to as a second measurement (CPICH-RSCP);

a measurement (PCCPCH-RSCP) specific to a predetermined second physical channel (PCCPCH) of the power of the signal received for a predetermined code (RSCP) of said second physical channel (PCCPCH), referred to as a third measurement (PCCPCH-RSCP); and

a measurement of power attenuation losses (PL) due to the propagation of the signals transmitted, referred to as a fourth measurement (PL).

3. ) Method according to claim 2, characterized in that, said type of measurement being said fourth measurement (PL), said first threshold value (Ttarget UL) is determined in accordance with the following formula:

Ttarget_UL_d=PLtarget UL dB - H1_UL dB - H2_UL dB (EC/IO) UL_dB+IBS₁_dBm —

IBS₂_dBm -XdB +ACIRULdB -Hi UL dB H²ULdB;

where;

PL<sub>target—

UL</sub> is a parameter representative of the power attenuation losses due to the propagation of the signals transmitted on the uplink determined in accordance with the following formula;

$P<br><br>\text{\hspace{1em}<br><br>}<br><br>L_{\mathrm{target\_UL}<br><br>\mathrm{\_dB}}={\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{UL\_dB}}+I_{{B<br><br>S}_1<br><br>\mathrm{\_dBm}}-I_{B<br><br>\text{\hspace{1em}<br><br>}<br><br>S_2<br><br>\mathrm{\_dBm}}-x_{d<br><br>\text{\hspace{1em}<br><br>}<br><br>B}+{\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{UL\_dB}};<br><br>$

${\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{U<br><br>\text{\hspace{1em}<br><br>}<br><br>L}$

is a service quality objective on the uplink from said first mobile station (MS),

I_BS1 is a total level of interference on the cell served by said first base station (BS₁),

I_BS2 is a total level of interference on the cell served by said second base station (BS₂),

x is an uplink dead zone reduction parameter,

ACIR_UL is a rate of interference on adjacent channels on the uplink determined in accordance with the following formula;

${\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{UL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{\mathrm{MS\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{{\mathrm{BS}}_2<br><br>\mathrm{\_dB}}}{10}}\right)<<br><br>0;<br><br>$

where;

ACLR_MS is a rate of rejection on adjacent channels in transmission from said first mobile station (MS), and

ACS_BS2 is a rate of selectivity of adjacent channels in reception by said second base station (BS₂),

H1_UL and H2_UL are hysteresis parameters relating to the uplink of said first (BS₁) and second (BS₂) base stations respectively, said hysteresis parameters being intended to provide a triggering margin for the calculation of said first threshold value (T<sub>target—

UL</sub>); and

/or

in that said second threshold value (T<sub>target—

DL</sub>) is determined in accordance with the following formula;

T<sub>target—

DL</sub> dB PLtargetDL_dB HlDL_dB - H²DL_dB =(Ec/lIO) DL_dB+PT BS2 dBm- P<sub>T—

DL</sub> dBm +ACIR_DL dB - ZdB - H1_DL dB H²DL_dB;

where;

PL<sub>target—

DL</sub> is a parameter representative of the power attenuation losses due to the propagation of the signals transmitted on the downlink determined in accordance with the following formula;

$P<br><br>\text{\hspace{1em}<br><br>}<br><br>L_{\mathrm{target\_DL}<br><br>\mathrm{\_dB}}={\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{DL\_dB}}+P_{{\mathrm{T\_BS}}_2<br><br>\mathrm{\_dBm}}-P_{\mathrm{T\_DL}<br><br>\mathrm{\_dBm}}+{\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{DL\_dB}}-z_{d<br><br>\text{\hspace{1em}<br><br>}<br><br>B};<br><br>$

where;

${\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{D<br><br>\text{\hspace{1em}<br><br>}<br><br>L}$

is a service quality objective on the downlink to said first mobile station (MS),

P<sub>T—

BS2</sub> is a level of total power transmitted on the cell served by said second base station (BS₂),

P<sub>T—

DL</sub> is a maximum level of transmit power, by said first base station (BS₁), allowed on the downlink between said first mobile station (MS) and said first base station (BS₁),

z is a downlink dead zone parameter,

H1_DL and H2_DL are hysteresis parameters relating to the downlink of said first (BS₁) and second (BS₂) base stations respectively, said hysteresis parameters being intended to provide a triggering margin for the calculation of said second threshold value (T<sub>target—

DL</sub>); and

ACIR_DL is a rate of interference on adjacent channels on the downlink determined in accordance with the following formula;

${\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{DL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{{\mathrm{BS}}_2<br><br>\mathrm{\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{\mathrm{MS\_dB}}}{10}}\right);<br><br>$

where;

ACLR_BS2 is a rate of rejection on adjacent channels in transmission from said second base station (BS₂), and

ACS_MS is a rate of selectivity of the adjacent channels in reception by said first mobile station (MS).

4. ) Method according to claim 2, characterized in that, said type of measurement being said third measurement (PCCPCH-RSCP), said first threshold value (Ttarget_uL) is determined in accordance with the following formula:

Ttarget_ULdB=PCCPCH_RSCPtarget_UL dB - Hl UL_dB - H²UL_dB =PLtargetULdB +TX PCCPCHBS₁ dB,,-TX_PCCPCHBS2 dBm-HiULdB-H2_UL dB;

where;

TX_PCCPCH_BS1 is a level of transmit power of said second physical channel (PCCPCH) from said first base station (BS₁),

TX_PCCPCH_BS2 is a level of transmit power of said second physical channel (PCCPCH) from said second base station (BS₂),

H1_UL and H2_UL are hysteresis parameters relating to the uplink of said first (BS₁) and second (BS₂) base stations respectively, said hysteresis parameters being intended to provide a triggering margin for the calculation of said first threshold value (T<sub>target—

UL</sub>),

PL<sub>target—

UL</sub> is a parameter representative of the power attenuation losses due to the propagation of the signals transmitted on the uplink determined in accordance with the following formula;

$P<br><br>\text{\hspace{1em}<br><br>}<br><br>L_{\mathrm{target\_UL}<br><br>\mathrm{\_dB}}={\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{UL\_dB}}+I_{{\mathrm{BS}}_1<br><br>\mathrm{\_dBm}}-I_{B<br><br>\text{\hspace{1em}<br><br>}<br><br>S_2<br><br>\mathrm{\_dBm}}-x_{d<br><br>\text{\hspace{1em}<br><br>}<br><br>B}+{\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{UL\_dB}};<br><br>$

where;

${\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{U<br><br>\text{\hspace{1em}<br><br>}<br><br>L}$

is a service quality objective on the uplink from said first mobile station (MS),

I_BS1 is a total level of interference on the cell served by said first base station (BS₁),

I_BS2 is a total level of interference on the cell served by said second base station (BS₂),

x is an uplink dead zone reduction parameter,

ACIR_UL is a rate of interference on adjacent channels on the uplink determined in accordance with the following formula;

${\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{UL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{\mathrm{MS\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{{\mathrm{BS}}_2<br><br>\mathrm{\_dB}}}{10}}\right)<<br><br>0;<br><br>$

where;

ACLR_MS is a rate of rejection on adjacent channels in transmission from said first mobile station (MS), and

ACS_BS2 is a rate of selectivity of the adjacent channels in reception by said second base station (BS₂); and

/or

in that said second threshold value (T<sub>target—

DL</sub>) is determined in accordance with the following formula;

T<sub>target—

DL—

dB</sub>=PCCPCH_RSCP<sub>target—

DL—

dB</sub>−

H1<sub>DL—

dB</sub>−

H2<sub>DL—

dB</sub>=PL<sub>target—

DL—

dB</sub>+TX_PCCPCH<sub>BS1−

dBm</sub>−

TX_PCCPCH<sub>BS2−

dBm</sub>−

H1<sub>DL—

dB</sub>−

H2<sub>DL—

dB</sub>;

where;

H1_DL and H2_DL are hysteresis parameters relating to the downlink of said first (BS₁) and second (BS₂) base stations intended to provide a triggering margin for the calculation of said second threshold value (T<sub>target—

DL</sub>)

PL<sub>target—

DL</sub> is a parameter representative of the power attenuation losses due to the propagation of the signals transmitted on the downlink determin ed in accordance with the following formula;

$P<br><br>\text{\hspace{1em}<br><br>}<br><br>L_{\mathrm{target\_DL}<br><br>\mathrm{\_dB}}={\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{DL\_dB}}+P_{{\mathrm{T\_BS}}_2<br><br>\mathrm{\_dBm}}-P_{\mathrm{T\_DL}<br><br>\mathrm{\_dBm}}+{\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{DL\_dB}}-z_{d<br><br>\text{\hspace{1em}<br><br>}<br><br>B};<br><br>$

where;

${\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{D<br><br>\text{\hspace{1em}<br><br>}<br><br>L}$

is a service quality objective on the downlink to said first mobile station (MS),

P<sub>T—

BS2</sub> is a level of total power transmitted on the cell served by said second base station (BS₂),

PT_DL is a maximum level of transmit power, by said first base station (BS₁), allowed on the downlink between said first mobile station (MS) and said first base station (BS₁),

z is a downlink dead zone parameter, and

ACIR_DL is a rate of interference on adjacent channels on the downlink determined in accordance with the following formula;

${\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{DL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{{\mathrm{BS}}_2<br><br>\mathrm{\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{\mathrm{MS\_dB}}}{10}}\right);<br><br>$

where;

ACLR_BS2 is a rate of rejection on adjacent channels in transmission from said second base station (BS₂), and

ACS_MS is a rate of selectivity of adjacent channels in reception by said first mobile station (MS).

5. ) Method according to claim 2, characterized in that, said type of measurement being said second measurement (CPICH-RSCP), said first threshold value (Ttarget UL) is determined in accordance with the following formula:

Ttarget_UL _dB=CPICH RSCPtarget UL_dB - HUL_dB - H²UL_dB =PLtarget_UL_dB+TX_CPICHBS₁ dBm -TX_CPICHBS2 dB -HiUL_dB -H²UL_dB;

where;

TX_CPICH_BS1 is a level of transmit power of said first physical channel (CPICH) from said first base station (BS₁),

TX_CPICH_BS2 is a level of transmit power of said first physical channel (CPICH) from said second base station (BS₂),

H1_UL and H2_UL are hysteresis parameters relating to the uplink of said first (BS₁) and second (BS₂) base stations respectively, said hysteresis parameters being intended to provide a triggering margin for the calculation of said first threshold value (T<sub>target—

UL</sub>)

PL<sub>target—

UL</sub> is a parameter representative of the power attenuation losses due to the propagation of the signals on the uplink determined in accordance with the following formula;

$P<br><br>\text{\hspace{1em}<br><br>}<br><br>L_{\mathrm{target\_UL}<br><br>\mathrm{\_dB}}={\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{UL\_dB}}+I_{{\mathrm{BS}}_1<br><br>\mathrm{\_dBm}}-I_{B<br><br>\text{\hspace{1em}<br><br>}<br><br>S_2<br><br>\mathrm{\_dBm}}-x_{d<br><br>\text{\hspace{1em}<br><br>}<br><br>B}+{\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{UL\_dB}};<br><br>$

where;

${\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{UL}}$

is a service quality objective on the uplink from said first mobile station (MS),

I_BS1 is a total level of interference on the cell served by said first base station (BS₁),

I_BS2 is a total level of interference on the cell served by said second base station (BS₂),

x is an uplink dead zone reduction parameter,

ACIR_UL is a rate of interference on adjacent channels on the uplink determined in accordance with the following formula;

${\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{UL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{\mathrm{MS\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{{\mathrm{BS}}_2<br><br>\mathrm{\_dB}}}{10}}\right)<<br><br>0;<br><br>$

where;

ACLR_MS is a rate of rejection on adjacent channels in transmission from said first mobile station (MS), and

ACS_BS2 is a rate of selectivity of adjacent channels in reception by said second base station (BS₂); and

/or

in that said second threshold value (T<sub>target—

DL</sub>) is determined in accordance with the following formula;

TtargetDLdB=CPICH_RSCPtargetDLdB - HlDL_dB - H²DL_dB =PLtarget_DL_dB+TX_CPICHBS₁_dB.-TX CPICHBS2 dBmHlDL dB-H²DL_dB;

where;

H1_DL and H2_DL are hysteresis parameters relating to the downlink of said first (BS₁) and second (BS₂) base stations respectively, said hysteresis parameters being intended to provide a triggering margin for the calculation of said second threshold value (T<sub>target—

DL</sub>)

PL<sub>target—

DL</sub> is a parameter representative of the power attenuation losses due to the propagation of the signals transmitted on the downlink determined in accordance with the following formula;

$P<br><br>\text{\hspace{1em}<br><br>}<br><br>L_{\mathrm{target\_DL}<br><br>\mathrm{\_dB}}={\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{DL\_dB}}+P_{{\mathrm{T\_BS}}_2<br><br>\mathrm{\_dBm}}-P_{\mathrm{T\_DL}<br><br>\mathrm{\_dBm}}+{\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{DL\_dB}}-z_{d<br><br>\text{\hspace{1em}<br><br>}<br><br>B};<br><br>$

where;

${\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{DL}}$

is a service quality objective on the downlink to said first mobile station (MS),

P<sub>T—

BS2</sub> is a level of total power transmitted on the cell served by said second base station (BS₂),

P<sub>T—

DL</sub> is a maximum level of transmit power, by said first base station (BS₁), allowed on the downlink between said first mobile station (MS) and said first base station (BS₁),

z is a downlink dead zone parameter, and

ACIR_DL is a rate of interference on adjacent channels on the downlink determined in accordance with the following formula;

${\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{DL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{\mathrm{BS2}<br><br>\mathrm{\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{\mathrm{MS\_dB}}}{10}}\right);<br><br>$

where;

ACLR₃S₂ is a rate of rejection on adjacent channels in transmission from said second base station (BS₂), and

ACS_MS is a rate of selectivity of the adjacent channels in reception by said first mobile station (MS)

6. ) Method according to claim 2, characterized in that, said type of measurement being said first measurement (CPICH-Ec/No), said first threshold value (T_target—

_UL) is determined in accordance with the following formula;

Ttarget UL dB=CPICH_EC/NOtarget UL dB - HlUL dB - H²UL_dB =PLtargetULdB +TX_CPICHBS,_dBm - TX_CPICHBs2 dBm - (RSSIsB_dB RSSIBS2 dBm)- HlULdB - H²UL_dB;

where;

TX_CPICH_BS1 is a level of transmit power of said first physical channel (CPICH) from said first base station (BS₁),

TX_CPICH_BS2 is a level of transmit power of said first physical channel (CPICH) from said second base station (BS₂),

RSSI_BS1 is a level of wideband power received from said first base station (BS₁),

RSSI_BS2 is a level of wideband power received from said second base station (BS₂),

H1_UL and H2_UL are hysteresis parameters relating to the uplink of said first (BS₁) and second (BS₂) base stations respectively, said hysteresis parameters being intended to provide a triggering margin for the calculation of said first threshold value (T<sub>target—

UL</sub>)

PL<sub>target—

UL</sub> is a parameter representative of the power attenuation losses due to the propagation of the signals transmitted on the uplink determined in accordance with the following formula;

$P<br><br>\text{\hspace{1em}<br><br>}<br><br>L_{\mathrm{target\_UL}<br><br>\mathrm{\_dB}}={\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{UL\_dB}}+I_{{\mathrm{BS}}_1<br><br>\mathrm{\_dBm}}-I_{B<br><br>\text{\hspace{1em}<br><br>}<br><br>S_2<br><br>\mathrm{\_dBm}}-x_{d<br><br>\text{\hspace{1em}<br><br>}<br><br>B}+{\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{UL\_dB}};<br><br>$

where;

${\left(\frac{E<br><br>\text{\hspace{1em}<br><br>}<br><br>c}{\mathrm{I0}}\right)}_{\mathrm{UL}}$

is a service quality objective on the uplink from said first mobile station (MS),

I_BS1 is a total level of interference on the cell served by said first base station (BS₁),

I_BS2 is a total level of interference on the cell served by said second base station (BS₂),

x is an uplink dead zone reduction parameter,

ACIR_UL is a rate of interference on adjacent channels on the uplink determined in accordance with the following formula;

${\mathrm{ACIR}}_{\text{\hspace{1em}<br><br>}<br><br>\mathrm{UL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{\mathrm{MS\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{\mathrm{BS2}<br><br>\mathrm{\_dB}}}{10}}\right)<<br><br>0;<br><br>$

where;

ACLR_MS is a rate of rejection on adjacent channels in transmission from said first mobile station (MS), and

ACS_BS2 is a rate of selectivity of adjacent channels in reception by said second base station (BS₂); and

/or

in that said second threshold value (T<sub>target—

DL</sub>) is determined in accordance with the following formula;

Ttarget DL dB=CPICH ECINOtarget DL dB - HiDL dB - H2_DL dB =PLtargetDLdB +TX CPICHBs₁ dBin - TX_CPICHBS₂ dBm - (RSSI_BS1 dBm RSSIBS2 dBm)- HlDL_dB - H²DL_dB;

where;

H1_DL and H2_DL are hysteresis parameters relating to the downlink of said first (BS₁) and second (BS₂) base stations respectively, said hysteresis parameters being intended to provide a triggering margin for the calculation of said second threshold value (T<sub>target—

DL</sub>),

PL<sub>target—

DL</sub> is a parameter representative of the power attenuation losses due to the propagation of the signals on the downlink determined in accordance with the following formula;

${\mathrm{PL}}_{\mathrm{target\_DL}<br><br>\mathrm{\_dB}}={\left(\frac{\mathrm{Ec}}{\mathrm{I0}}\right)}_{\mathrm{DL\_dB}}+P_{{\mathrm{T\_BS}}_2<br><br>\mathrm{\_dBm}}-P_{\mathrm{T\_DL}<br><br>\mathrm{\_dBm}}+{\mathrm{ACIR}}_{\mathrm{DL\_dB}}-z_{\mathrm{dB}};<br><br>$

where;

${\left(\frac{\mathrm{Ec}}{\mathrm{I0}}\right)}_{\mathrm{DL}}$

is a service quality objective on the downlink to said first mobile station (MS),

P<sub>T—

BS2</sub> is a level of total power transmitted on the cell served by said second base station (BS₂),

P<sub>T—

DL</sub> is a maximum level of transmit power, by said first base station (BS₁), allowed on the downlink between said first mobile station (MS) and said first base station (BS₁),

z is a downlink dead zone parameter, and

ACIR_DL is a rate of interference on adjacent channels on the downlink determined in accordance with the following formula;

${\mathrm{ACIR}}_{\mathrm{DL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{{\mathrm{BS}}_2<br><br>\mathrm{\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{\mathrm{MS\_dB}}}{10}}\right);<br><br>$

where;

ACLR_BS2 is a rate of rejection on adjacent channels in transmission from said second base station (BS₂), and

ACS_MS is a rate of selectivity of adjacent channels in reception by said first mobile station (MS).

7. ) Method according to any of claims 3 to 6, characterized in that the values of said hysteresis parameters relating to the uplink and/or to the downlink of said first (BS₁) and second (BS₂) base stations are not zero.

8. ) Method according to any of claims 3 to 7, characterized in that said method furthermore comprises:

a step of storing, by said first mobile station (MS), a rate (ACLR<sub>MS—

spec</sub>) of rejection on adjacent channels in transmission from said first mobile station (MS), said rate (ACLR<sub>MS—

spec</sub>) of rejection on adjacent channels being specific to said first mobile station, and a step of determination of said rate (ACIR_UL) of interference on adjacent channels on the uplink in accordance with the following formula;

${\mathrm{ACIR}}_{\mathrm{UL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{\mathrm{MS\_spec}<br><br>\mathrm{\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{\mathrm{BS2\_dB}}}{10}}\right)<<br><br>0;<br><br>$

where ACS_BS2 is a rate of selectivity of adjacent channels in reception by said second base station (BS₂); and

/or

a step of storing, by said first mobile station (MS), a rate (ACS<sub>MS—

spec</sub>) of selectivity of adjacent channels in reception by said first mobile station (MS), said rate (ACS<sub>MS—

spec</sub>) of selectivity of adjacent channels being specific to said first mobile station (MS), and a step of determination of said rate (ACIRDL) of interference on adjacent channels on the downlink in accordance with the following formula;

${\mathrm{ACIR}}_{\mathrm{DL\_dB}}=10·<br><br>{\log }_{10}<br><br>\left({10}^{\frac{-{\mathrm{ACLR}}_{\mathrm{BS2}<br><br>\mathrm{\_dB}}}{10}}+{10}^{\frac{-{\mathrm{ACS}}_{\mathrm{MS\_spec}<br><br>\mathrm{\_dB}}}{10}}\right)<<br><br>0;<br><br>$

where ACLR_BS2—

dB

is a rate of rejection on adjacent channels in transmission from said second base station (BS₂).

9. ) Method according to any of claims 3 to 8, characterized in that said first base station (BS₁) transmits, to said first mobile station (MS), a signal comprising at least one first configuration message for configuring said first mobile station (MS), said first configuration message comprising at least one first information element, said at least one first information element being representative of at least one parameter belonging to the group comprising:

said service quality objective

${\left(\frac{\mathrm{Ec}}{\mathrm{I0}}\right)}_{\mathrm{UL}}$

on the uplink from said first mobile station (MS);

said total interference level (I_BS1) allowed on the cell served by said first base station;

said total interference level (I_BS2) allowed on the cell served by said second base station;

said uplink dead zone reduction parameter (x);

said rate (ACLR_MS) of rejection on adjacent channels by said second base station in transmission from said first mobile station (MS);

said rate (ACS_BS2) of selectivity of adjacent channels in reception by said second base station (BS₂); and

said first threshold value (T<sub>target—

UL</sub>); and

/or in that said first base station (BS₁) transmits, to said first mobile station (MS), a signal comprising at least one second configuration message for configuring said first mobile station (MS), said second configuration message comprising at least one second information element, said at least one second information element being representative of at least one parameter belonging to the group comprising;

said service quality objective

${\left(\frac{\mathrm{Ec}}{\mathrm{I0}}\right)}_{\mathrm{DL}}$

on the downlink to said first mobile station (MS);

said level (P<sub>T—

BS2</sub>) of total power transmitted on the cell served by said second base station (BS₂);

said maximum level (P<sub>T—

DL</sub>) of transmit power, by said first base station (BS₁), allowed on the downlink between said first mobile station (MS) and said first base station (BS₁);

said downlink dead zone reduction parameter (z);

said rate (ACS_MS) of selectivity of adjacent channels in reception by said first mobile station (MS);

said rate (ACLR_BS2) of rejection on adjacent channels in transmission from said second base station (BS₂);

said second threshold value (T<sub>target—

DL</sub>); and

a second maximum threshold value (T<sub>target—

DL—

Max</sub>)

10. ) Method according to claim 8, characterized in that said first base station (BS₁) transmits, to said first mobile station (MS), a signal comprising at least one third configuration message for configuring said first mobile station, said third configuration message comprising at least one third information element, said at least one third information element being representative of a first intermediate threshold value (T_{intermediary—}

_UL) determined in accordance with the following formula;

11. ) Method according to claim 8 or 10, characterized in that said first mobile station (MS) transmits, to said first base station (BS₁), a signal comprising at least one fifth configuration message, said fifth configuration message comprising at least one fifth information element, said at least one fifth information element being representative of said stored rate (ACLR_MS—

_spec) of rejection on adjacent channels specific to said first mobile station (MS), said first base station (BS₁) determines said first threshold value (T<sub>target—

UL</sub>) as a function of said specific rate (ACLR<sub>MS—

spec</sub>) of rejection on adjacent channels, and transmits said first threshold value (TtargetUL) to said first mobile station (MS); and

/or

in that said first mobile station (MS) transmits, to said first base station (BS₁), a signal comprising at least one sixth configuration message, said sixth configuration message comprising at least one sixth information element, said at least one sixth information element being representative of said rate (ACS<sub>MS—

spec</sub>) of selectivity of adjacent channels specific to said first mobile station (MS), said first base station (BS₁) determines said second threshold value (T<sub>target—

DL</sub>) as a function of said specific rate (ACS<sub>MS—

spec</sub>) of selectivity of adjacent channels, and transmits said second threshold value (T<sub>target—

DL</sub>) to said first mobile station (MS).

12. ) Method according to any of the preceding claims, characterized in that at least said first (T_target—

_UL) threshold value and/or said second (T<sub>target—

DL</sub>) threshold value is split into at least first (T<sub>1—

target—

UL</sub>, T<sub>1—

target—

DL</sub>) and/or second (T<sub>2—

target—

UL</sub>, T<sub>2—

target—

DL</sub>) partial threshold values relating to, said first (BS₁) and second (BS₂) base stations respectively, and whose difference, expressed in dB, is equal to said first (T<sub>target—

UL</sub>) and/or second (T<sub>target—

DL</sub>) threshold values respectively,

and in that said first base station (BS₁) transmits, to said first mobile station (MS), a signal comprising at least one seventh configuration message for configuring said first mobile station, said seventh configuration message comprising at least one seventh information element, said at least one seventh information element being representative of at least one parameter belonging to the group comprising;

said first partial threshold value (T<sub>1—

target—

UL—

dB</sub>) relating to the uplink dead zone relating to said second base station (BS₂);

said first partial threshold value (T<sub>1—

target—

DL—

dB</sub>) relating to the downlink dead zone relating to said first base station (BS₁)

said second partial threshold value (T<sub>2—

target—

UL</sub>) relating to the uplink dead zone relating to said second base station (BS₂);

said second partial threshold value (T<sub>2—

target—

DL—

dB</sub>) relating to the downlink dead zone relating to said first base station (BS₁);

a first maximum partial threshold value (T<sub>1—

target—

UL—

Max</sub>) relating to the uplink dead zone relating to said second base station (BS₂);

a first maximum partial threshold value (T<sub>1—

target—

DL—

Max</sub>) relating to the downlink dead zone relating to said first base station (BS₁).

13. ) Method according to claim 12, characterized in that, said seventh configuration message comprising said first maximum partial threshold value (T_1target—

<sub>UL—

Max</sub>) relating to the uplink dead zone relating to said second base station (BS₂),

said method comprises the following steps of;

providing said first mobile station (MS) with said first threshold value (T<sub>target—

UL</sub>);

utilization, by said first mobile station (MS), of said first maximum partial threshold value (T<sub>1target—

UL—

Max</sub>) relating to the uplink dead zone relating to said second base station (BS₂) as first partial threshold value (T<sub>1—

target—

UL</sub>) relating to the uplink dead zone relating to said second base station (BS₂);

determination, by said first mobile station (MS), of said second partial threshold value (T<sub>2—

target—

UL</sub>) relating to the uplink dead zone relating to said second base station (BS₂); and

/or

in that, said seventh configuration message comprising said first maximum partial threshold value (T<sub>1target—

DL—

Max</sub>) relating to the downlink dead zone relating to said first base station (BS₁), said method comprises the following steps of;

providing said first mobile station (MS) with said second threshold value (T<sub>target—

DL</sub>);

utilization, by said first mobile station (MS), of said first maximum partial threshold value (T₁target_DL_Max) relating to the downlink dead zone relating to said first base station (BS₁) as first partial threshold value (T<sub>1—

target—

DL</sub>) relating to the downlink dead zone relating to said first base station (BS₁);

determination, by said first mobile station (MS), of said second partial threshold value (T<sub>2—

target—

DL</sub>) relating to the downlink dead zone relating to said first base station (BS₁).

14. ) Method according to claim 12 or 13, characterized in that said comparison step comprises the comparison of the value of said first and second parameters (Q_f1, Q_f2) with said first (T_1—

<sub>target—

UL</sub> or T<sub>1—

target—

DL</sub>) and second (T<sub>2—

target—

UL</sub> or T<sub>2—

target—

DL</sub>) partial threshold values respectively, said radio link implemented on at least said first frequency (f_1-UL) and/or said third frequency (f_1-DL) between said first mobile station (MS) and said first base station (BS₁) being interrupted;

when the value of said first parameter (Q_f1) is less than said first partial threshold value (T<sub>1—

target—

DL—

dB</sub>) relating to said downlink dead zone relating to said first base station (BS₁) and the value of said second parameter (Q_f2) is greater than said second partial threshold value (T<sub>2—

target—

DL—

dB</sub>) relating to said downlink dead zone relating to said first base station (BS₁), and/or

when the value of said first parameter (Q_f1) is less than said first partial threshold value (T<sub>1—

target—

UL</sub>) relating to the uplink dead zone relating to said second base station (BS₂) and the value of said second parameter (Q_f2) is greater than said second partial threshold value (T<sub>2—

target—

UL</sub>) relating to the uplink dead zone relating to said second base station (BS₂).

15. ) Method according to any of claims 12 to 14, characterized in that, to carry out said comparison step, said first base station (BS₁) transmits, beforehand, to said first mobile station (MS), a signal comprising an eighth configuration message for configuring said first mobile station (MS), said eighth configuration message comprising at least one eighth information element, said at least one eighth information element being representative of at least one event relating to the interruption of said radio link between said first mobile station (MS) and said first base station (BS₁), said at least one event belonging to the group comprising:

an event of type 1e,

an event of type 1f,

an event of type 2a,

an event of type 2b,

an event of type 2c, and

an event of type 2d.

16. ) Method according to any of the preceding claims, characterized in that, to interrupt said radio link between said first mobile station (MS) and said first base station (BS₁), said first mobile station (MS) triggers a radio link failure procedure.

17. ) Method according to any of the preceding claims, characterized in that said first mobile station (MS) interrupts said radio link with said first base station (BS₁) following the receipt of a signal, said signal comprising at least one ninth configuration message for configuring said first mobile station, said ninth configuration message comprising at least one ninth information element, said at least one ninth information element allowing said first mobile station (MS) to interrupt said radio link.

18. ) Method according to claim 15, characterized in that said method comprises, after the transmission of the signal comprising said eighth configuration message and before the interruption of the radio link between said first base station (BS₁) and said first mobile station (MS), a step comprising:

transmission, from said first base station (BS₁) to said first mobile station (MS), of at least one message belonging to the group comprising;

a radio bearer reconfiguration message;

a radio bearer release message;

a transport channel reconfiguration message; and

a physical channel reconfiguration message.

19. ) Method according to claim 16 or 17, itself dependent on claim 16, characterized in that, to trigger said radio link failure procedure, said first base station (BS₁) transmits, beforehand, to said first mobile station (MS), a signal comprising a tenth configuration message, said tenth configuration message comprising at least one tenth information element, the value of said at least one tenth information element being representative of the trigger action or of the non-trigger action of said radio link failure procedure.

20. ) Method according to claim 19, characterized in that said tenth configuration message comprises, furthermore, at least one eleventh information element, the value of said at least one eleventh information element being representative of the type of said at least one event triggering said radio link failure procedure.

21. ) Method according to any of claims 15 to 18, itself dependent on claim 15, characterized in that the transmission to said first mobile station (MS) of said eighth configuration message relating to at least one event is carried out, if and only if, said first mobile station (MS) is present in a zone which is potentially an uplink dead zone relating to said second base station (BS₂) and/or a downlink dead zone relating to said first base station (BS₁).

22. ) Method according to any of the preceding claims, characterized in that, before interrupting said radio link between said first mobile station (MS) and said first base station (BS₁), said first mobile station (MS) transmits, to said first base station (BS₁), at least said first and second estimated parameters (Q_f1, Q_f2) representative of the qualities of reception of the signals transmitted from said first (BS₁) and second (BS₂) base stations to said first mobile station (MS) on said third (f_1-DL) and fourth (f_2-DL) frequencies.

23. ) Mobile telecommunication system comprising a plurality of base stations and of mobile stations, in which at least one base station and at least one mobile station implement in order to communicate a frequency division duplex mode and/or the wideband code division multiple access technology, characterized in that said mobile telecommunication system implements said method of reducing at least one dead zone relative to a first base station (BS₁) and/or at least one second base station (BS₂) according to any of the preceding claims.

24. ) Mobile station (MS), referred to as a first mobile station, of the type comprising means for communicating with at least one first base station (BS₁) on at least one first frequency (f_1-UL), at least one second base station (BS₂) being next to said first base station (BS₁),

characterized in that, at least one other mobile station (MS′

), referred to as a second mobile station, communicating with said second base station (BS₂) on at least one second frequency (f_2-UL), said first mobile station comprises means of;

estimation of at least one first (Q_f1) and/or one second (Q_f2) parameters, said first parameter (Q_f1) being representative of the quality of reception of the signals transmitted by said first base station (BS₁) and received by said first mobile station (MS) on a third frequency (f_1-DL), said second parameter (Q_f2) being representative of the quality of reception of the signals transmitted by said second base station (BS₂) and received by said first mobile station (MS) on a fourth frequency (f_2-DL),

determination of a third parameter (Q<sub>f1—

dB</sub>-Q<sub>f2—

dB</sub>), said third parameter being dependent on said at least one first (Q_f1) estimated parameter and/or one second (Q_f2) estimated parameter,

comparison of the value of said third determined parameter with a predetermined first threshold value (T<sub>target—

UL</sub>), said first threshold value being representative of a dead zone on the uplink between said second mobile station (MS′

) and said second base station (BS₂) for at least said second frequency (f_2-UL), said dead zone being referred to as a uplink dead zone, said uplink dead zone relating to said at least one second base station (BS₂), and/or

comparison of the value of said third determined parameter with a predetermined second threshold value (T<sub>target—

DL</sub>), said second threshold value being representative of a dead zone on the downlink between said first base station (BS₁) and said first mobile station (MS) for at least said third frequency (f_1-DL), said dead zone being referred to as a downlink dead zone, said downlink dead zone relating to at least said first base station (BS₁), and,

if the value of said third parameter (Q<sub>f1—

dB</sub>-Q<sub>f2—

dB</sub>) exceeds said first threshold value (T<sub>target—

UL</sub>) and/or said second threshold value (T<sub>target—

DL</sub>), said first mobile station interrupts the radio link implemented on at least said first frequency (f_1-UL) and/or said third frequency (f_1-DL) between said first mobile station (MS) and said first base station (BS₁).

25. ) Mobile station (MS) according to claim 24, characterized in that said first mobile station (MS) furthermore comprises:

means of storing a rate (ACLR<sub>MS—

spec</sub>) of rejection on adjacent channels in transmission by said first mobile station (MS), said rate (ACLR<sub>MS—

spec</sub>) of rejection on adjacent channels being specific to said first mobile station (MS); and

/or

means of storing a rate (ACS<sub>MS—

spec</sub>) of selectivity of adjacent channels in reception by said first mobile station (MS), said rate (ACS<sub>MS—

spec</sub>) of selectivity of adjacent channels being specific to said first mobile station (MS).