La teoría y la práctica de la ocupabilidad en la educación social

The system table contains the descriptions of all the systems that are permitted to provide service or prohibited from providing service. Each system is described in a system record. See Figure 4-12.

Figure 4-12 Example Editor View of a System Table

The system table is comprised of a minimum of one and up to 16,384 system records; the actual number may be subject to the physical amount of storage available on the device. See section 4.6. Each system record describes one or more CDMA systems that are permitted or prohibited.

In the context of the PRL a system is identified by a broadcast identity ([System Identification, Network Identification] or [Mobile Country Code, Mobile Network Code]) and the frequency band on which the system was found (see section 1.1.2 )

System records are explicitly grouped together. Groups of systems are termed

Geographical Areas (as was described in section 2.2.5 ). Permitted (or preferred)

systems in can be assigned a priority. Priority ordering in the system table is explicit unlike the implicit priority ordering of the records in the acquisition table. Priority ordering

6 _{In Band-class 5 only channels 126 through 275 are valid or conditionally valid for block A, only channels}

106 through 235 are valid for Block B and only channels 26 through 168 are valid for Block C. See 3GPP2 C.P0057 for details on valid channels and frequencies.

only has scope and relevance within the grouping context of the Geographical Area. An example of what a system table might look like in a PRL editor is given in Figure 4-12.

4.5.1 System Type and System Record Type

In defining system records, a PRL editor often allows the specification of a system type. The system type in the PRL editor is in descriptive form (‘1x/IS-95,’ ‘HRPD/IS-856’ for 1xEV-DO etc.). The system type would generally translate to a system record type. One thing to be aware of is that system record types did not exist prior to IS-683-C when a new form of system record was introduced, known as the extended system record

format. The extended system record format enabled the PRL description of systems with

different sets of attributes than those used to describe the basic 1x/IS-95 systems. The first such system to be defined as a new type was the high rate packet data system (1xEV-DO). Prior to this, all system records were of the same type, which is referred to in this document as the Basic System Record. Often when people talk of the extended PRL, they are referring to the extended record formats that are offered in IS-683C. With the increasing presence of 1xEV-DO systems the use of extended system record format is becoming more common.

With the new extended system record format it became possible to identify a type of system record as an explicit field. The system types as given in a PRL editor and the types of system records used to describe them in the actual PRL system table are listed Table 4-21.

Table 4-21 Editor System Types and Corresponding System Record Types

Types of System Record & Relationship Standard

Version _{PRL Editor System Type Standard System Record Type}

683-A, 683-B IS-95, CDMA2000 1x Only one [Basic] System Record [Basic] System Record

IS-95, CDMA2000 1x

Extended System Record, TYPE= 0 683-C

High Rate Packet Data (IS-856,1xEV-DO) Extended System Record, TYPE= 1’ [Basic] System Record

IS-95, CDMA2000 1x

Extended System Record, TYPE= 0

IS-856 (1xEV-DO) Extended System Record, TYPE= 1

683-E

Table 4-22 SSPR_P_REV Values and Meaning

SSPR_P_REV value Supports PRL

conforming to

SSPR_P_REV value Supports PRL

conforming to

1 IS-683-A 3 IS-683-C

2 IS-683-B 4 IS-683-D

As can be seen from the table the basic system record of IS-683 A and B can be expressed in a the extended system record format using a Type=0.

A stored variable in the mobile device indicates which type of PRL that the device can support. This variable is called SSPR_P_REV. An SSPR_P_REV value of ‘1’ indicates that the only the basic record formats can be supported. An SSPR_P_REV of ‘3’ indicates support of an Extended Preferred Roaming List containing Extended System Records.

4.5.2 Basic 1x/IS-95 System Record

The systems that are to be preferred or barred are described in a system record of the system table. An editor view of the system table is shown in Table 4-13. Each line is a system record. The specific fields of a system record are shown in Figure 4-13

Figure 4-13 Example Editor View of a IS95/CDMA200 1x/IS-95 System Record

Table 4-23 [Basic] System Record Fields (IS-683 A & B)

System Record Field Length (bits)

SID 15 NID_INCL 2 NID 0 or 16 PREF_NEG 1 GEO 1 PRI 0 or 1 ACQ_INDEX 9 ROAM_IND 0 or 8

4.5.2.1 Negative/Preferred

This field is set to ‘1’ if the mobile station is allowed to operate on the system associated with this record. This field is set to ‘0’ if the mobile station is not allowed to operate on the system associated with this record.

4.5.2.2 Geography

The concept of a GEO was introduced in section 2.2.5. This field is how that strategy of segmentation of the system table is implemented. If this is the first system record, this field is set to ‘0.’ If this is not the first system record, then this field is set as follows: If the system associated with this record is in the same geographical region as the system associated with the previous system record, this field is set to ‘1’; otherwise, this field is set to ‘0.’

In an editor this is normally seen as ‘SAME’ and ‘NEW’ as opposed to ‘1’ and ‘0.’ The important aspect of the GEO flag is that it is a relative description with respect to the

previous system table entry; i.e. a GEO is either the ‘SAME’ as the previous or it is not

the same as the previous in which case it is ‘NEW’: another GEO. 4.5.2.3 Priority

Only a preferred system can have priority, negative systems are all equally disliked and equally prohibited, so if the PREF_NEG field of this system record is equal to ‘0’ then this field is omitted. Preferred systems on the other hand can be declared in preference order, and indeed systems can share the same level of preference. The declaration of preference is the implicit instruction to the handset’s system selection function that it must try and always reach the most-preferred system.

The priority field is a relative description with respect to the next system table entry; i.e. priority is either the ‘SAME’ as the next or it is ‘MORE’ than the next record. Since priority only has relevance within the context of a Geographical area, the last preferred system record in a GEO, or if the next record describes a prohibited system, this field has no meaning and is set to ‘0.’

If the system associated with this system record is more desirable than the system associated with the next system record, this field is set to ‘1.’ If the system described by this system record is as desirable as the next described system (i.e. it has the same priority) then this field is set to ‘0.’

The important thing to remember here is that unlike the GEO, the priority setting of a system record affects the subsequent record.

4.5.2.4 Acquisition Index

This field is set to the index of the acquisition record that specifies the acquisition parameters for the system associated with this record. (The index of the nth acquisition record is n-1.) For example, the index of the first acquisition record in ACQ_TABLE is 0, and the index for the fourth acquisition record is 3.

4.5.2.5 Roam Indicator

Only a preferred (or available) system will display a roaming indicator. Negative systems will not be able to provide service; hence, for those systems, this field is omitted.

4.5.2.6 SID - System Identification

This field is set to the SID broadcast by the system that this record represents. The SID is a 15-bit binary field that can be represented by a 5-digit decimal number between 0 and 32,763. A non-zero value for SID is a specific broadcast SID. The value of ‘0’ serves

as a SID wildcard and is generally described as any other SID that is not specified in any other system record.

A specific or wildcard SID still means that the system is on a frequency described by the acquisition record associated with it by the ACQ_INDEX.

4.5.2.7 NID - Network Identification

The NID is an optional field and its presence is indicated by the use of the NID_INCL field. A NID_INCL value equal to ‘01’ indicates that the NID is included and is set to the NID of the network associated with this record; otherwise, this field is omitted.

The maximum NID value (65535) denotes any NID (i.e., serves as an NID wildcard). Not including the NID field is equivalent to including it and setting it to ‘1111111111111111.’ The value ‘0’ denotes a NID of the public system.

Table 4-24 shows the values and meaning of the NID_INCL field.

Table 4-24 The NID Included Field

NID_INCL

Parameter Description

‘00’ NID not included. Assume NID value ‘1111111111111111’

‘01’ NID included

‘10’ NID not included. Assume NID value ‘0000000000000000’ ‘11’ Reserved