Content for  TS 43.064  Word version:  18.0.0

The Fast Ack/Nack reporting procedure (FANR) refers to the possibility to include, in a radio block for data transfer sent in one direction, piggy-backed ack/nack information relative to a TBF with FANR activated in the other direction. This is achieved by inserting a fixed-size piggy-backed ack/nack (PAN) field in the radio block. When a PAN field is inserted, a suitable Puncturing Scheme variant for the modulation and coding schemes in use is chosen, so that the RLC data field and the PAN field fit together in the radio block along with the RLC/MAC header. The presence of the PAN field, is signalled by the PAN indicator bit in the RLC/MAC header. When this bit is set the receiver shall use the corresponding Puncturing Scheme variant of the CPS indicated in the RLC/MAC header to decode the RLC data field. If a mobile station is assigned a TBF with FANR activated, all concurrent TBFs assigned to the mobile station shall have FANR activated irrespective of the RLC/MAC mode of each TBF (acknowledged mode, non-persistent mode or unacknowledged mode). Fast Ack/Nack reporting is not supported in GPRS TBF mode.

In RTTI configuration, a radio block consisting of four bursts is sent using two PDCHs, i.e. a PDCH-pair, in each of two consecutive TDMA frames. In RTTI configuration, the time to transmit a radio block is half of a basic radio block period. In RTTI configuration, a downlink TBF assignment consists of a number of PDCH-pairs, each PDCH-pair comprising two PDCHs. In a downlink dual carrier configuration (see sub-clause 3.3.4), up to 8 PDCH-pairs may be assigned per TBF. In a single carrier configuration up to 4 PDCH-pairs may be assigned per TBF. Two PDCHs constituting a downlink PDCH-pair need not be contiguous. In RTTI configuration, an uplink TBF assignment consists of up to four PDCH-pairs. The two PDCHs constituting an uplink PDCH-pair need not be contiguous. The PACCH shall have the same TTI configuration as the TBF with which it is associated. In each direction PDCH-pairs cannot be assigned so that they are partially overlapped, i.e. two different PDCH-pairs cannot have one PDCH in common. For an uplink TBF in RTTI configuration USFs can be sent in one of two ways:

• RTTI USFs: a USF is sent in one reduced radio block period, i.e. a USF is mapped on four bursts transmitted on a downlink PDCH-pair during two consecutive TDMA frames. The USF allocates resources for one or four uplink radio blocks in the next reduced radio block period(s), depending on the value of USF_GRANULARITY.
• BTTI USFs: two USFs are sent in a basic radio block period. One USF is mapped on four bursts transmitted on the first PDCH of a downlink PDCH-pair during four consecutive TDMA frames. This USF allocates resources for one or four uplink radio blocks in the first 2 TDMA frames of the next basic radio block period(s), depending on the value of USF_GRANULARITY. A second USF is mapped on four bursts transmitted on the second PDCH of a downlink PDCH-pair during four consecutive TDMA frames. This USF allocates resources for one or four uplink radio blocks in the second 2 TDMA frames of the next basic radio block period(s), depending on the value of USF_GRANULARITY.

For each TBF, the network signals the corresponding TTI configuration (i.e. either basic or reduced) at TBF establishment/ reconfiguration. In case of RTTI configuration, the network also signals at uplink TBF establishment/reconfiguration the USF mode (i.e. either RTTI or BTTI) to be used for that TBF. For each assigned uplink PDCH-pair, the network may signal at TBF establishment/reconfiguration the "corresponding downlink PDCH-pair", i.e. the DL PDCH-pair where USFs and PACCH/D are monitored. The timeslot numbers of the PDCHs constituting an uplink PDCH-pair may be different from those of the PDCHs constituting the corresponding downlink PDCH-pair. If no indication is provided, the corresponding downlink PDCH-pair will be the one with the same timeslot numbers as the uplink PDCH-pair. On a given downlink PDCH-pair all USFs shall be sent with the same USF mode. For a given mobile station, in each direction, the same TTI configuration shall be used for all TBFs (and PACCHs) assigned with one or more PDCH(s) in common in that direction. If a TBF is assigned on completely different PDCH(s) the TTI used may be different. For a given mobile station, different uplink TBFs may use different USF modes if assigned on completely different PDCH(s). A PDCH may be shared between RTTI TBF and BTTI TBF (assigned to different mobile stations). Alternatively, both PDCHs forming a PDCH-pair may be assigned to only support RTTI TBFs. RTTI configuration is not supported in GPRS TBF mode.

A mobile station supporting EGPRS2 in the downlink supports additional modulation and coding schemes on the downlink.

A mobile station supporting EGPRS2 in the uplink supports additional modulation and coding schemes on the uplink.

Power Efficient Operation (PEO) is used by a MS to reduce its power consumption through the use of relaxed mobility related requirements and extended DRX (eDRX) or Power Saving Mode (PSM). A PEO capable MS shall support at least one of eDRX or PSM. When eDRX or PSM has been successfully negotiated a PEO capable MS can choose to enable PEO in a cell that supports PEO in which case it enables the use of relaxed mobility related requirements and use the EGPRS PACKET CHANNEL REQUEST message indicating 'PEO One Phase Access Request' when attempting packet access. The mobility related requirements for a MS that has enabled PEO are relaxed compared to a MS that has not enabled PEO, and are referred to as relaxed mobility related requirements. The relaxation includes:

• No periodic measurements of the serving and non-serving cells are required.
  • Measurements of only the serving cell need to be performed before each time the paging block is monitored or each uplink transmission;
  • Measurements for cell reselection are only triggered if at least one, out of a set of criteria used to determine the suitability of the serving cell, is fulfilled based on the measurements of the serving cell.
  • Fewer non-serving cells, compared to MS not in PEO, need to be considered in measurements for cell reselection;
• System Information (SI) acquisition required only before each time the paging block is monitored or each uplink transmission and in this case only if more than 24 h have passed since last acquisition, or, a change in SI is detected;
• Only autonomous cell reselection supported in idle mode;
• No mobility related procedures need to be supported in packet transfer mode and no neighbour cell measurements need to be performed when in packet transfer mode.

For more detailed procedures, see TS 45.008. A cell indicates its support of PEO in the SI13 Rest Octets IE, see TS 44.018. In this case it supports the reception of an EGPRS PACKET CHANNEL REQUEST message indicating 'PEO One Phase Access Request' (see TS 44.018 and TS 44.060) from a MS attempting packet access. When eDRX is supported, the number of blocks per 51-multiframe reserved for AGCH is subject to the requirement that all cells in the routing area shall have the same number of paging blocks per 51-multiframe (see TS 45.002). DTM is not supported in PEO. Support of PEO is optional for the MS and the network. The MS shall disable PEO in case it enters a cell that does not support PEO. The MS may also disable PEO (see TS 45.008) at any time, in which case it operates as if it was in a cell that does not support PEO. A MS that chooses to disable PEO shall disable the use of relaxed mobility related requirements and the EGPRS PACKET CHANNEL REQUEST message indicating 'PEO One Phase Access Request'. PEO makes use of a 9 bit BSIC wherein the 6 bit BSIC is supplemented with a 3 bit Radio frequency Colour Code with the purpose to help distinguish between cells in tight frequency reuse networks. A PEO capable mobile station may support deferred System Information acquisition (see subclause 3.3.8.2).

In order to reduce energy consumption in packet idle mode, the network may broadcast information to assist the MS to apply deferred SI acquisition for PEO (see TS 45.008). To this purpose it reconfigures SI 13 for a given cell to include the PEO Idle Mode Mobility Cell Group Description comprising cells, geographically adjacent or close to each other, with shared cell parameters related to cell (re)selection, Routing Area assignment, paging monitoring, mobility support and cell barring and assigns it a broadcast frequency list containing BCCH carriers allocated in these cells. To better match cell deployments, some cell parameters may deviate from the common values and are separately indicated on a per cell basis (see TS 44.018). To allow for different settings of shared cell parameters in geographic adjacent areas, different PEO Idle Mode Mobility (IMM) cell groups are defined with an identifier to distinguish one from the other, thus providing a spatially definite assignment of cells to PEO IMM cell groups. Since values of shared or non-shared cell parameters in a particular PEO IMM cell group are subject to change in time, a change mark is assigned to the PEO IMM cell group. An increment of the change mark for a particular PEO IMM cell group hence indicates to the MS the requirement to acquire the complete SI in the serving cell. To enable fast detection if a non-serving cell, subject to BSIC identification for the purpose of identifying candidates for cell reselection in idle mode, is part of a given PEO IMM cell group or not, the PEO IMM Cell Group Identifier and the related PEO IMM Change Mark are sent in AGCH/PCH messages along with RCC being required for BSIC identification. Thus, an MS supporting deferred SI acquisition for PEO reads AGCH/PCH messages of a non-serving cell to identify both the PEO IMM Cell Group Identifier and the PEO IMM Change mark. If both values match with those of the serving cell, it will not need to read the BCCH for this cell prior to the decision for cell reselection, neither after cell reselection to this cell for subsequent cell reselections and for paging monitoring in packet idle mode. Only in case a matching page is received (matching IMSI or P-TMSI of the MS), that requires to send a paging response, or the MS needs to perform an uplink data transmission, or a timeout since the last reading of the complete SI in a different than the serving cell (current cell) is expired, the MS is required to read the complete System Information in the serving cell. The network may choose to deactivate deferred SI acquisition for PEO in network deployments for which System Information needs to be reconfigured more frequently or for which adjacent cells' idle mode mobility parameters differ too much. The support of deferred SI acquisition for PEO is broadcasted in System Information (SI 13).