A METHOD OF CONFIGURING DEFAULT VALUES FOR CELL RE-

SELECTION IN A WIRELESS COMMUNICATION SYSTEM

TECHNICAL FIELD

The present invention relates to a method of configuring default values, and more

particularly, to a method of configuring default values for cell re-selection in a wireless

communication system.

BACKGROUND ART

Global System for Mobile Communication (GSM) was developed to bring together

different communication systems. Further, General Packet Radio Service (GPRS)

introduced packet switched data into GSM systems. The GPRS provides packet data service

which means that multiple users can share the same transmission channel, only transmitting

when there is data to send. GSM can be referred to as circuit-switched data service which

establishes a radio resource (RR) connection and reserves the full bandwidth of that circuit-

switched data during the lifetime of the RR connection. The difference with packet data

service is that the packet data service can have total available bandwidth dynamically

dedicated to those users who are actually sending at any given moment, providing higher

utilization where users only send or receive data intermittently.

Enhanced Data Rate for GSM Evolution (EDGE) introduced 8-phase shift keying

(8-PSK) into GSM/GPRS networks. EDGE can use 8-PSK as well as Gaussian Minimum

Shift Keying (GMSK) of GSM as the modulation scheme. With an exception of modulation

scheme of GPRS, most of non-modulation techniques of GPRS can be applied to EDGE.

In the GSM, the GPRS, and/or the EDGE can be in various states or modes such as

an idle mode, packet transfer mode, packet idle mode, and dual transfer mode. Here, the

packet idle mode is based on packet switched (PS) service and is used when there is no

traffic between a mobile station (MS) and a network.

As known, the MS can enjoy mobility between cells/sectors. In addition, the MS can

move from one cell/sector to another cell/sector during various modes (e.g., idle mode). To

put differently, the MS can move from a source cell to a target cell during idle mode. Here,

the source cell refers to a cell in which the MS is currently located, and the target cell refers

to the cell to which the MS seeks to enter or move. The process describing movement from

the source cell to the target cell can be referred to as cell re-selection process.

DISLCOSURE OF THE INVENTION

TECHNICAL SOLUTION

Accordingly, the present invention is directed to a method of configuring default

values for cell re-selection in a wireless communication system that substantially obviates

one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a method of configuring values of

cell re-selection parameters for cell re-selection from a serving cell to a neighboring cell in

a wireless communication system.

Additional advantages, objects, and features of the invention will be set forth in part

in the description which follows and in part will become apparent to those having ordinary

skill in the art upon examination of the following or may be learned from practice of the

invention. The objectives and other advantages of the invention may be realized and

attained by the structure particularly pointed out in the written description and claims hereof

as well as the appended drawings.

To achieve these objects and other advantages and in accordance with the purpose of

the invention, as embodied and broadly described herein, a method of configuring values of

cell re-selection parameters for cell re-selection from a serving cell to a neighboring cell in

a wireless communication system includes receiving from a network a first message via a

first control channel, wherein the first message includes values of a first group of cell

selection parameters, assigning pre-stored values of the cell selection parameters for the

serving cell to values of a second group of the cell selection parameters, if the first message

does not include the values of the second group of the cell selection parameters, and

calculating the values of the cell re-selection parameters using the values of the first and the

second groups of the cell selection parameters.

It is to be understood that both the foregoing general description and the following

detailed description of the present invention are exemplary and explanatory and are

intended to provide further explanation of the invention as claimed.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding

of the invention and are incorporated in and constitute a part of this application, illustrate

embodiment(s) of the invention and together with the description serve to explain the

principle of the invention. In the drawings;

FIG. IA is an exemplary diagram illustrating reception of a packet measurement

order message from the network;

FIG. IB is an exemplary diagram illustrating calculation of a packet measurement

order message from the network; and

FIG. 2 is an exemplary flowchart illustrating a process of setting the default values.

BEST MODE FORCARRYINGOUTTHE INVENTION

Reference will now be made in detail to the preferred embodiments of the present

invention, examples of which are illustrated in the accompanying drawings. Wherever

possible, the same reference numbers will be used throughout the drawings to refer to the

same or like parts.

Figure IA is an exemplary diagram illustrating reception of a packet measurement

order message from the network. By transmitting the packet measurement order message,

the network orders the MS to calculate necessary parameter(s) for cell re-selection and

provides information for network control measurement (NC) reporting. If the parameters for

the NC measurements are not included, then a previous packet measurement order message

belonging to the same set of messages can still be considered valid.

The packet measurement order message from the network can be transmitted to the

MS on a packet common control channel (PCCCH) or a packet associated control channel

(PACCH). If the information does not fit into one message (or the size of the information

exceeds the message capacity), the remaining information can be sent in other packet

measurement order message.

Figure IB is an exemplary diagram illustrating calculation of a packet measurement

order message from the network. More specifically, the MS can use the information

included in the packet measurement order message (e.g., neighbor cell measurement

reporting) to calculate the parameter(s) for cell re-selection. In calculating the parameter(s),

default value(s) can be used as well. Thereafter, the MS can transmit a packet measurement

result message, including the calculated parameter(s), to the network.

A detailed description of the packet measurement order message as well as

information related to neighbor cells will be described hereinafter.

A packet measurement order message includes network control (NC) measurement

parameters. The NC measurement parameters provides the parameters for the serving cell

and may contain frequency list deviations (add/delete) to the GPRS, for example, either on

the PBCCH or on broadcast control channel (BCCH). As shown below in a part of a packet

measurement order information elements table, Table 1, the NC measurement parameters

are included as an optional element in the packet measurement order message.

[Table 1]

< Packet Measurement Order message content > : : = < PAGE_M0DE : bit (2) > { { 0 < Global TFI : < Global TFI IE > > I 10 < TLLI / G-RNTI : bit (32) > } { < PM0_INDEX : bit (3) > < PMO_COUNT : bit (3) > { 0 1 1 < NC Measurement Parameters : < NC Measurement Parameters struct > > }

The "NC measurement parameters struct" contains the network control order, the

NC parameters, and an NC frequency list struct. If the value of the network control order or

any of the NC parameters differs between instances of the message, the value of the

parameter in the instance with the highest PM0_INDEX can be used or considered valid

and all others can be ignored.

The purpose of the PMOJNDEX field and the PMO_COUNT field is to indicate

the number of individual messages within the sequence of the packet measurement order

messages and to assign an index to identify each one of them. The PMO_INDEX field is

binary coded with a range of 0 to 7, and provides an index to identify the individual packet

measurement order message. Similarly, the PMO_COUNT field is binary coded with a

range of 0 to 7, and provides the PM0_INDEX value for the last (highest indexed) message

is the sequence of packet measurement order messages. Furthermore, the measurement

order is not affected by the MS until all instances of the packet measurement order message

are received.

If global TFI field is present, this information element indicates the MS to which

this message is addressed. In addition, if TLLI/G-RNTI, which is a 32-bit field, is present,

this field also indicates the MS to which this message is addressed.

As optional element, the packet measurement order message may or may not include

the NC Measurement parameters. If the message includes these parameters, the structure of

the NC measurement parameters can be shown as in Table 2.

[Table 2]

< NC Measurement Parameters struct > : : = < NETWORK_C0NTROL_ORDER : bit (2) > { 0 I K NC_ N0N_DRX_PERI0D : bit (3) >

< NC_REPORTING_PERIOD_I : bit (3) >

< NCJtEPORTINGJPERIODJT : bit (3) > }

{ 0 I K NC FREQUENCY LIST : < NC Frequency list struct > > }

Referring to Table 2, the NC measurement parameters include mandatory elements

as well as optional elements. More specifically, as a mandatory requirement, the NC

measurement parameter may include the NETWORK_CONTROL_ORDER parameter.

Moreover, as the optional parameters NC_NON_DRX_PERIOD_I, NC_REPORTING_

PERIODJT, and the NC_FREQUENCY_ LIST may be included. Each of these optional

parameters can be represented by a 3 -bit field.

Furthermore, the NETWORK_CONTROL_ORDER field can be coded according to

the following table - Table 3.

[Table 3]

As an element of the NC measurement parameters, the NC_FREQUENCY_LIST

parameter can be provided as optional element. If, however, the NC_FREQUENCY_LIST

is present, then an exemplary structure of the list can be as follows as shown in Table 4.

[Table 4]

< NC Frequency list struct > : : =

{ 0 I 1 { < NR_OF_REMOVED_FREQ : bit (5) >

{ < REMOVED_FREQ_INDEX : bit (6) > } * (1 + val(NR_OF_REMOVED_FREQ)) } { 1 < List of added Frequency struct : < Add Frequency list struct > >} ** Q;

As emphasized by bold type, a list of added frequency structure can be included in

the NC frequency list. As shown in Table 4, the NR_OF_REMOVED_FREQ is a 5 bit field,

and l+val(NR_OF_REMOVED_FREQ) indicates the number of frequencies in the list

which may not be used for NC measurements and provides the number of instances of the

parameter REMOVED_FREQ_INDEX.

In addition, the REMOVED_FREQ_INDEX is a 6-bit field and is used to indicate

the index to the frequency to be removed in the GPRS sent on the PBCCH or on the BCCH.

Further, included in the "NC frequency list struct" can be a deviation list which

contains removed or added frequencies to a different list (e.g., GPRS list).

As one of the optional elements of the list of added frequency structure, cell

selection parameters can be included. Hence, if the cell selection parameters (emphasized in

bold) are included in the list of added frequency structure, then a cell structure comprising

the cell selection parameters can be shown as in Table 5.

[Table 5]

< Add Frequency list struct > : : =

< START_FREQUENCY : bit (10) >

< BSIC : bit (6) >

{ 0 I 1 < Cell selection params : < Cell Selection struct > > } <NR_OF_FREQUENCIES : bit (5) >

< FREQ_DIFF_LENGTH : bit (3) >

{ < FREQUENCY_DIFF : bit (l+val(FREQ_DIFF_LENGTH)) > < BSIC : bit (6) >

{ 0 I 1 < Cell selection params : < Cell Selection struct > > } } (val(NR OF FREQUENCIES));

Referring to Table 5, the "Add Frequency list struct" contains the frequency list for

the NC parameters. More specifically, START_FREQUENCY, FREQ_DIFF_LENGTH,

and FREQUENCY_DIFF are represented by a 10-bit field, a 3 -bit field, and a

(l+val(FREQ_DIFF_LENGTH) bit field, respectively. Moreover, the BSIC is a 6-bit field

and is encoded as the "Base Station Identity Code" with a range of 0 to 63.

The "Cell selection params" in the "Add Frequency list struct" can be present for the

first neighbor cell added by the message. As an abnormal case, if the "Cell selection

params" is missed (not present) for the first neighbor cell added by the message, then the

same parameters as the serving cell can be applied as default value.

Furthermore, a structure (or cell selection structure) of the cell selection parameters

can be represented as in Table 6.

[Table 6]

Referring to Table 6, the parameters, such as GPRS_RXLEV_ ACCESS_MIN,

GPRS_MS_TXPWR_MAX_CCH, GPRS_TEMPORARY_OFFSET,

GPRS_PENALTY_TIME, GPRS_RESELECT_OFFSET, PRIORIT Y_CLAS S OF HCS

params, HCS_THR, and SI13_PBCCH_LOCATION, are optional parameters that can be

used to cell re-selection.

With respect to the packet measurement order message, if any parameter or a part of

a parameter (e.g., element) related to neighboring cell(s) is not included, there is no default

value that can be used in its place. More detailed discussions related to unavailability of the

default value(s) is discussed below in terms of possible cases or situations.

The discussion of default values for the parameters associated with the first

neighboring cell in the packet measurement order message as shown below in following

cases or situations (Case#l - Case#3) can be found in Table 11.2.9b.2 of section 12.2.9b of

3GPP TS 44.060 V.6.180. The same parameters, as described below, can also be found in

3GPP TS 44.060 V7.5.0.

First, consider a case (i.e., Case #1) in which cell selection parameters are not

provided (or missed) in the packet measurement order message but the PCCCH is present in

the serving cell. Table 7 illustrates this case.

[Table 7]

CELL_BAR_ACCESS_2 : Serving cell CELL_BAR_ACCESS_2

EXC_ACC : Serving cell EXC_ACC

SAME_RA_AS_SERVTNG_CELL: The cell is in the same Routing Area as the serving cell

GPRS_RXLEV_ACCESS_MIN : Serving cell GPRS_RXLEV_ACCESS_MIN

GPRS_MS_TXPWR_MAX_CCH: Serving cell GPRS_MS_TXPWR_MAX_CCH

GPRS_TEMPORARY_OFFSET : Serving cell GPRSJTEMPORARY OFFSET

GPRS_PENALTY_TIME : Serving cell GPRS_PENALTY_TIME

GPRSJtESELECTJOFFSET : 0 dB

HCSJTHR : Serving cell HCSJTHR

PRIORITY_CLASS : Serving cell PRIORITY_CLASS

SIl 3 PBCCH LOCATION : Undefined.

As indicated in this case, if the cell selection parameters (or cell selection params)

are not provided for the first neighbor cell added by the message, then the same parameters

as the serving cell can be applied as the default value.

Second, Case #2 considers where the cell selection parameters are not provided (or

present) in the packet measurement order message and the PCCCH is also not provided (or

present) in the serving cell, as shown in Table 8.

[Table 8]

CELL_BAR_ACCESS_2 : Serving cell CELL_BAR_ACCESS

EXC_ACC : Serving cell cell exclusive access support capability

SAME RA AS SERVING CELL: The cell is in the same Routeing Area as the serving cell

Third, Case #3 considers where the cell selection parameters are provided (or

present) in the packet measurement order message but the optional parameters are not

provided (or present) in whole or in part.

[Table 9]

GPRS RXLEV ACCESS MIN : Serving cell RXLEV ACCESS MIN

GPRS MS TXPWR MAX CCH : Serving cell MS TXPWR MAX CCH

GPRS TEMPORARY OFFSET : Serving cell TEMPORARY_OFFSET

GPRS PENALTY TIME : Serving cell PENALTY TIME

GPRS RESELECT OFFSET : O dB

HCS THR : infinity

PRIORITY CLASS : undefined

SI13 PBCCH LOCATION : undefined

The definitions of the parameters, such as CELL_BAR_ACCESS_2, EXC_ACC,

SAME_RA_AS_SERVING_CELL, GPRS_RXLEV_ACCESS_MIN, RXLEV

_ACCESS_MIN, GPRS_MS_TXPWR_MAX_CCH, GPRS_MS_TXPWR_MAX_CCH,

GPRS_TEMPORARY_OFFSET, GPRS_PENALTY_TIME, GPRS_RESELECT_OFFSET,

HCSJTHR, PRIORITYJXASS, and SI13_PBCCH_LOCATION, are provided in 3GPP

TS 45.008 or 3GPP TS 44.060. Therefore, discussions related to definitions of these

parameters will be omitted.

Furthermore, default values are provided to address possibilities of Cases #1 - #3. A

packet system information type 3 (PSI3) includes the parameters used as default values for

optional parameters in the packet measurement order message, and a PSI3 message is

usually transmitted via a packet broadcast control channel (PBCCH). However, as discussed,

the packet measurement order message is based on the PCCCH, and as a result, the origin of

the default value(s) may become ambiguous.

In short, since the parameters are defined with respect to the PCCCH, the MS may

not be able to perform efficient and/or effective cell re-selection since the PBCCH was not

considered in order to get the information from a PSI3 message.

As discussed, the MS can freely move from one cell to another cell in the wireless

communication environment. It is also possible for the MS to move to another cell while in

a packet idle mode. Here, the cell which currently hosts the MS can be referred to as a

source cell, and the cell to which the MS moves to can be referred to as a target cell.

If the MS moves from the source cell to the target cell during the packet idle mode,

the MS can perform cell re-selection. Prior to performing the cell re-selection process, the

MS receives a packet measurement order message from the network, requesting the MS to

measure various information for cell re-selection.

The MS uses the information related to neighbor cells (or list) included in the packet

measurement order message and calculates certain parameters associated with cell re-

selection. For example, the MS can calculate a cell ranking criterion parameter (i.e., C32).

Here, C32 can be used for selection of a specific cell from the neighboring cell(s) having

the same priority and can be defined as follows as shown in Equation 1.

[Equation 1]

C32(s) = Cl(s)

C32(n) = Cl(n) + GPRS_RESELECT_OFFSET(n) - T0(n) * (1 - L(n))

Referring to Equation 1, C32(s) and C32(n) respectively denote the cell priority of

parameters associated with the serving cell and the neighboring cell. Moreover, Cl(s) and

Cl(n) denote a path loss criterion parameter for the serving cell and the neighboring cell,

respectively. The path loss criterion parameter, or Cl, can be defined by Equation 2.

[Equation 2]

Cl = (A-Max(B, O))

A = RLA_P - GPRS_RXLEV_ACCESS_MIN

B = GPRS MS TXPWR MAX CCH - P

Referring to Equation 2, RLA_P denotes received level averages, and

GPRS_RXLEV_ACCESS_MIN denotes a minimum received signal level requested to the

MS for system access. Moreover, GPRS_MS_TXPWR_MAX_CCH denotes a maximum

transmit power level requested to the MS for system access until other order is given, and P

denotes a maximum radio frequency (RF) output power by the MS.

In Equation 1, GPRS_RESELECT_OFFSET parameter is for applying prescribed

offset value and/or hysteresis value to each cell. In addition, T0(n) and L(n) can be further

defined as follows as shown in Equation 3.

[Equation 3]

T0(n) = GPRS_TEMPORARY_OFFSET(n) * H(GPRS_PENALTY_TME(n) - T(n))

L(n) = 0 if PRIORITY_CLASS(n) = PRIORITY_CLASS(s)

= 1 if PRIOPJTY_CLASS(n) φ PRIORITY_CLASS(s)

Referring to Equation 3, GPRS_TEMPORARY_OFFSET indicates a negative offset

which is applied to C31/C32 during GPRS_PENALTY_TIME after timer, T, is initiated in

the corresponding cell. Here, timer T is initiated for each cell selected from a list of carriers

having the strongest signals. In other words, timer T is initiated for cells having the

strongest signals. If the MS moves to one of the cells having the strongest signals, then

timer T is initiated starting from 0. However, if the serving cell is one of the cells listed in

the list during the cell re-selection process, timer T is set to the value of

GPRS_PENALTY_TIME. Moreover, H(x) = 0 (for x < 0), 1 (for x > 0).

As discussed, parameters such as GPRS_RXLEV_ACCESS_MIN, GPRS_MS_

TXPWR_MAX_CCH, GPRS_RESELECT_OFFSET, GPRS_TEMPORARY_ OFFSET,

GPRS_PENALTY_TIME, PRIORITY_CLASS, and PRIORIT Y CLAS S, HCS_THR,

SIl 3_PBCCH_LOCATION are optional parameters.

If these optional parameters are excluded or not present in the packet measurement

order message for the first neighbor cell, default value(s) can be used instead. As discussed,

with respect to cell re-selection, there can be complications associated with

PCCCH/PACCH-based packet measurement order message in terms of using the default

values, especially if the PBCCH is present in the serving cell. The following

discussions/examples address situations take into account reference to system information

received on the broadcast control channel (e.g., PBCCH) for configuring default values

associated with cell re-selection.

Depending on the situation of the MS, the default value(s) can be configured

accordingly. The following are examples of four (4) cases. For more detailed description,

Figure 2 can be referred to as an exemplary flowchart illustrating a process of setting the

default values.

First, Case #1 represents a situation where cell selection parameters for the

neighboring cell(s) are not provided (or not present) in the packet measurement order

message but PBCCH is provided in the serving cell. Hence, the PSB message can be

received via the PBCCH. Here, the MS can refer to PSD message received via the PBCCH

and set/assign the default values for the parameters which are excluded (or not present) in

the received packet measurement order message for the first neighbor cell. That is, the MS

uses the parameter values of the PSI3 message and assigns the same values to the

corresponding parameters whose values are not provided in the packet measurement order

message. As for the remaining parameters, predetermined default values can be used.

1

The PSI3 message is transmitted via the PBCCH, and the structure of the PSD

message including the mandatory parameters are shown in Table 10.

[Table 10]

< PSI3 message content > : : =

< PAGE_MODE : bit (2) >

< PSI3_CHANGE_MARK : bit (2) >

< PSI3_BIS_COUNT : bit (4) >

< Serving Cell parameters : < Serving Cell params struct > >

< Serving Cell params struct > : : =

< CELL_BAR_ACCESS_2 : bit >

< EXC_ACC : bit >

< GPRS_RXLEV_ACCESS JVIIN : bit (6) >

< GPRS_MS_TXPWR_MAX_CCH : bit (5) >

{ 0 I 1 < HCS Serving Cell parameters : < HCS struct > > }

< MULTIBAND REPORTING : bit (2) >;

Referring to Table 10, the serving cell parameters included in the PSB message

include CELL_BAR_ACCESS_2, EXC_ACC, GPRS_RXLEV_ACCESS_MIN,

GPRS_MS_TXPWR_MAX_CCH, MULTIBAND_REPORTING, HCSJTHR of HCS

struct, and PRIORITY_CLASS.

If the HCS struct is omitted for the serving cell, HCS is not used and the HCS

parameters for the other cells can be neglected (i.e., the HCS signal strength threshold shall

be set to infinity for all cells). Otherwise PRIORITY_CLASS and HCS_THR are defined.

The use of the HCS parameters is defined in 3GPP TS 45.008 (See Table 6).

The default values associated with Case #1 can be defined as follows as shown in

Table 11.

[Table 11]

CELL_BAR_ACCESS_2 : Serving cell CELL_BAR_ACCESS_2

EXC_ACC : Serving cell EXC_ACC

SAME_RA_AS_SERVING_CELL: The cell is in the same RouteingArea as the serving cell GPRS_RXLEV_ACCESS_MIN : Serving cell GPRS_RXLEV_ACCESS_MIN GPRS_MS_TXPWR_MAX_CCH: Serving cell GPRS_MS_TXPWR_MAX_CCH GPRS_TEMPORARY_OFFSET: 0 dB GPRS_PENALTY_TIME : Undefined

GPRS RESELECT OFFSET : 0 dB

HCS THR : Serving cell HCS THR

PRIORITY CLASS : Serving cell PRIORITY CLASS

SI13 PBCCH LOCATION : Undefined.

Second, Case #2 represents a situation where cell selection parameters are not

provided (or present) in the packet measurement order message and the PBCCH is also not

provided (or present) in the serving cell.

[Table 12]

CELLJBAR_ACCESS_2 : Serving cell CELL_BAR_ACCESS

EXC_ACC : Serving cell cell exclusive access support capability

SAME RA AS SERVING CELL: The cell is in the same RouteingArea as the serving cell

Referring to Table 12, the PBCCH is not present in the serving cell.

In such a case, the PSD message cannot be received via the PBCCH. Therefore, the

MS can rely on a system information type 3 (SI3) message, which is transmitted via a

broadcast control channel (BCCH), to apply the default value(s) for the mandatory

parameter(s) for the neighboring cell(s).

Similarly to above, the MS uses the parameter values of the SI3 message and assigns

the same values to the corresponding parameters whose values are not provided in the

packet measurement order message.

The SI3 message can include various elements as shown in Table 13.

[Table 13]

A more detailed description of the information elements (IE) of the cell selection

parameters (in bold) are shown in Figure 14.

[Table 14]

The cell selection parameters list included in the SD message includes the cell

selection parameters IE list. Furthermore, mandatory parameters such as

MSJTXPWR_MAX_CCH and RXLEV_ACCESS_MIN are assigned to prescribed octets

(e.g., Octet 2 and Octet 3) of the cell selection parameters IE list.

The default values of the first neighbor cell(s) with respect to Case #2 is shown in

Table 15.

[Table 15]

CELL BAR ACCESS 2 : Serving cell CELL_BAR_ACCESS_2

EXC ACC : Serving cell EXC_ACC

SAME RA AS SERVING CELL : The cell is in the same Routeing Area as the serving cell

GPRS RXLEV ACCESS MIN : Serving cell RXLEV ACCESS MIN

GPRS_MS_TXPWR_MAX_CCH : Serving cell MS_TXPWR_MAX_CCH

GPRS TEMPORARY OFFSET : 0 dB

GPRS PENALTY TIME : Undefined

GPRS RESELECT OFFSET : O dB

HCS THR : infinity

PRIORITY CLASS : Undefined

SIl 3 PBCCH LOCATION : Undefined

Third, Case #3 represents a situation where the cell selection parameters for the first

neighbor cell are provided (or present) in the packet measurement order message but some

of the optional parameters are not provided and the PBCCH is not provided (or present) in

the serving cell.

In this case, the SB message transmitted on the BCCH can be referred to by the MS

to apply the necessary default values for the first neighbor cell. That is, the MS uses the

parameter values of the SI3 message and assigns the same values to the corresponding

parameters whose values are not provided in the packet measurement order message.

Further, the optional parameters which are not present in the message can be affected by the

following parameters as shown in Table 16.

[Table 16]

GPRS RXLEV ACCESS MIN : Serving cell RXLEV ACCESS MIN

GPRS MS TXPWR MAX CCH : Serving cell MS TXPWR MAX CCH

GPRS TEMPORARY OFFSET : O dB

GPRS PENALTY TIME : Undefined

GPRS RESELECT OFFSET : O dB

HCS THR : infinity

PRIORITY CLASS : undefined

SI13 PBCCH LOCATION : undefined

Fourth, Case #4 represents a situation where the cell selection parameters for the

first neighbor cell are provided (or present) in the packet measurement order message but

some of the optional parameters are not provided and the PBCCH is provided (or present) in

the serving cell. This is shown in Table 17 as follows.

[Table 17]

GPRS RXLEV ACCESS MIN : Serving cell GPRS RXLEV ACCESS MIN

GPRS MS TXPWR MAX CCH : Serving cell GPRS MS TXPWR MAX CCH

GPRS TEMPORARY OFFSET : O dB

GPRS PENALTY TIME : Undefined

GPRS RESELECT OFFSET : O dB

HCS THR : Serving cell HCS THR

Referring to Table 17, unlike in Case #2 and Case #3 in which the SD message was

looked at since the PBCCH was not present. However, in Case #4, the PBCCH is present in

the serving cell and hence, the PSB message can be referred to for applying the default

value(s) for the first neighbor cell. That is, the MS uses the parameter values of the PSI3

message and assigns the same values to the corresponding parameters whose values are not

provided in the packet measurement order message.

In the discussion of above with respect to Cases #1 - #4, the PBCCH of the serving

cell is referred to for applying the default value(s) for the first neighboring cell, and the

default value(s) can be derived from (or based on) the PSI3 or SI3 message transmitted on

the PBCCH or BCCH, respectively. In particular, the cell selection parameters exist but do

not provide certain parameters, the parameter values provided in the PSI3 (or SI3) message

can be used. Furthermore, a default value for GPRS_TEMPORARY_OFFSET parameter

can be set to "0 dB," and a default value for GPRS_PENALTY_TIME parameter can be set

as "undefined" so that C32(s) = Cl(s) and C32(n) = Cl(n) can be established in Equation 1.

Further, the discussion above related to cell re-selection can be implemented in an

apparatus. That is, an apparatus associated with wireless communication system can be used

to implement the cell re-selection process.

INDUSTRIAL APPLICABILITY

It will be apparent to those skilled in the art that various modifications and variations

can be made in the present invention without departing from the spirit or scope of the

inventions. Thus, it is intended that the present invention covers the modifications and

variations of this invention provided they come within the scope of the appended claims and

their equivalents.