EDGE性能提高参数修改建议

EDGE性能提高参数修改建议
根据集团公司对EDGE的要求，我们希望能够提供更高的EDGE性能，因此希望进行对EDGE参数进行调整，下表为EDGE相关参数
由于不同小区的无线环境及配置情况有差异，因此我们希望能针对不同的小区进行不同参数配置的测试，从而得到优化经验，使局方和我们在以后的优化工作中能更好地设置这些参数。

下面将详细介绍各个参数。

一．CELL级别的参数
1.bep_period and bep_period2
●bep_period
Description
The bep_period parameter is used in an EGPRS cell to indicate the BEP (Bit Error Probability) filter averaging period used for filtering channel quality measurements by the mobile.A BSS software process is notified whenever the bep_period element value is changed.
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The EGPRS feature must be unrestricted.
Syntax
Change command strings
chg_element bep_period <value> <location> <cell_desc>
chg_cell_element bep_period <value> <cel_desc_opt>
Display command strings
disp_cell <cell_id> [“full”]
disp_element bep_period <location> <cell_desc>
Values
Value type Integer (BEP filter averaging period)
Valid range 0 to 10
Default value 0 Eliminates forgetting factor 'e' from channel quality measurement algorithms executed by the MS.
●bep_period2
Description
The bep_period2 parameter is optionally used in an EGPRS cell to further indicate the BEP (Bit Error Probability) filter averaging period used for filtering channel quality measurements by the mobile.
The bep_period2 parameter is a forgetting factor for the mobile station to use when filtering the Bit Error Probability. If this parameter is sent, the mobile station in the cell uses it, until the mobile station in the same cell receives a new bep_period2, or the mobile station leaves the cell or the MS enters packet idle mode.
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The EGPRS feature must be unrestricted.
Syntax
Change command strings
chg_element bep_period2 <value> <location> <cell_desc>
chg_cell_element bep_period2 <value> <cel_desc_opt>
Display command strings
disp_cell <cell_id> [“full”]
disp_element bep_period2 <location> <cell_desc>
Values
Value type Integer (Secondary BEP filter averaging period)
Valid range 0 to 15
Default value 15 Allows normal filtering
BEP的报告周期，用于控制无线抖动。

下表为BEP相关参数
2．egprs_init_dl_cs and egprs_init_ul_cs
egprs_init_dl_cs
Description
The egprs_init_dl_cs parameter specifies the initial downlink coding scheme to be used for an EGPRS TBF in a cell.
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The EGPRS feature must be unrestricted.
Syntax
Change command strings
chg_element egprs_init_dl_cs <value> <location> <cell_desc>
chg_cell_element egprs_init_dl_cs <value> <cell_desc_opt>
Display command strings
disp_cell <cell_id> [“full”]
disp_element egprs_init_dl_cs <location> <cell_desc>
Values
Value type Integer
Valid range 0 to 8
0 MCS1 is applied to start on downlink TBF for this cell.
1 MCS
2 is applied to start on downlink TBF for this cell.
2 MCS
3 is applied to start on downlink TBF for this cell.
3 MCS
4 is applied to start on downlink TBF for this cell.
4 MCS
5 is applied to start on downlink TBF for this cell.
5 MCS
6 is applied to start on downlink TBF for this cell.
6 MCS
7 is applied to start on downlink TBF for this cell.
7 MCS8 is applied to start on downlink TBF for this cell.
8 MCS9 is applied to start on downlink TBF for this cell.
Default value 2 The default value is 2 because MCS3 is considered to be safe to start the downlink transfer for all mobiles, when there is no prior information of a mobiles RF channel quality, regardless of where they are in the cell.
egprs_init_ul_cs
Description
The egprs_init_ul_cs parameter specifies the initial uplink coding scheme to be used for an EGPRS TBF in the cell.
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The EGPRS feature must be unrestricted.
Syntax
Change command strings
chg_element egprs_init_ul_cs <value> <location> <cell_desc>
chg_cell_element egprs_init_ul_cs <value> <cell_desc_opt>
Display command strings
chg_element egprs_init_ul_cs <value> <location> <cell_desc>
chg_cell_element egprs_init_ul_cs <value> <cell_desc_opt>
Values
Value type Integer
Valid range 0 to 8
0 MCS1 is applied to start on uplink TBF for this cell.
1 MCS
2 is applied to start on uplink TBF for this cell.
2 MCS
3 is applied to start on uplink TBF for this cell.
3 MCS
4 is applied to start on uplink TBF for this cell.
4 MCS
5 is applied to start on uplink TBF for this cell.
5 MCS
6 is applied to start on uplink TBF for this cell.
6 MCS
7 is applied to start on uplink TBF for this cell.
7 MCS8 is applied to start on uplink TBF for this cell.
8 MCS9 is applied to start on uplink TBF for this cell.
Default value 2 The default value is 2 because MCS3 is considered to be safe to use for uplink data packets after contention resolution for all mobiles, when there is no prior information of a mobiles RF channel quality, regardless of where they are in the cell.
增大起始编码优点是对于FTP的慢启动改善较明显，但对于小区内无线质量不好的手机可能造成无法使用的后果。

因此可以在无线环境比较好的条件下适当增大起始编码，如CQT测试的小区。

3．gprs_bs_cv_max
Description
The gprs_bs_cv_max specifies the maximum count down value a mobile can use for uplink RLC data transfer. The MS sends a count down value in each uplink RLC data block starting
gprs_bs_cv_max blocks from the last block. The value sent is decremented by one in each subsequent block. This allows the network to identify the last RLC block in the uplink TBF. Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The GPRS feature must be unrestricted.
BSS software processes using this parameter are notified immediately after the change is made. Syntax
Change command strings
chg_element gprs_bs_cv_max <value> <location> <cell_desc>
chg_cell_element gprs_bs_cv_max <value> <cell_desc_opt>
Display command string
disp_element gprs_bs_cv_max <location> <cell_desc>
Values
Value type Integer (blocks)
Valid range 0 to 15
Default value 6
4．gprs_pc_alpha
Description
The gprs_pc_alpha is the system parameter broadcast on the BCCH. It is used as a multiplier of the power offset in power control calculations. The actual multiplying factor is one-tenth of the value set in this parameter; that is, if N is the value of this parameter, the multiplying factor is N/10.
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The GPRS feature must be unrestricted.
BSS software processes using this parameter are notified immediately after the
change is made.
Syntax
Change command strings
chg_element gprs_pc_alpha <value> <location> <cell_desc>
chg_cell_element gprs_pc_alpha <value> <cell_desc_opt>
Display command strings
disp_cell <cell_id> “full”
disp_element gprs_pc_alpha <location> <cell_desc>
Values
Value type Integer (Power offset is multiplied by one tenth of this value)
Valid range 0 to 10
Default value 0
ALPHA：该参数设定了在使用手机GPRS动态功率控制时，与路径损耗的对应关系中手机发射功率减少的等级.
优化目的：可减少上行干扰和减少MS的功耗以保持平均待机时间.
5．gprs_t3192
Description
The gprs_t3192 timer specifies the MS timers used by the BTS on BCCH blocks. This parameter specifies the time that the MS continues the assigned PDCHs after receiving its last data block and before it returns to monitoring its paging groups.
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The GPRS feature must be unrestricted.
Syntax
Change command strings
chg_element gprs_t3192 <value> <location> cell_desc>
chg_cell_element gprs_t3192 <value> <cell_desc_opt>
Display command string
disp_element gprs_t3192 <location> <cell_desc>
Values
Value type Select integer (milliseconds)
Valid range 0, 80, 120, 160, 200, 500, 1000, and 1500
Default value 500
Timer3192，默认值为0.5 秒，这个参数会影响TBF 建立的时间长短。

常规情况下，当一组数据RLC 传完之后，手机会启动T3192，再等待0.5 秒钟(注意刚才在使用PDTCH 时隙)，如果没有续传的指令，T3192 超时后，会释放掉下行TBF 而且开始监视Paging 信道。

当再次有数据传时，需要重新立即指配。

这无形中，延长了TBF 建立时间。

T3192 的改到1 秒后对小数据交互多的GPRS 业务(如HTTP 浏览)或重选等TBF 变更频繁的地方(如小区较多的路测地段)的速度上有改善,而对于定点的稳定大数据量的FTP 下载没有绝对的正面或负面影响。

6．max_ms_dl_buffer
Description
The max_ms_dl_buffer parameter specifies the maximum size of the downlink buffer allocated
to every MS in the cell.
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The GPRS feature must be unrestricted.
BSS software processes using this parameter are notified immediately the change
is made.
Syntax
Change command strings
chg_element max_ms_dl_buffer <value> <location> <cell_desc>
chg_cell_element max_ms_dl_buffer <value> <cell_desc_opt>
Display command string
disp_element max_ms_dl_buffer <location> [<cell_desc>]
Values
Value type Integer (bytes.)
Valid range 5120 to 64000
5120 bytes
...
...
...
64000 bytes
Default value 38400 bytes
用于流控，此参数还有待研究。

7．tlli_blk_coding
Description
The tlli_blk_coding parameter is used to request the mobile station to use the coding scheme commanded for the Temporary Block Flow (TBF) even for RLC blocks containing the contention
resolution Temporary Logical Link Identifier (TLLI).
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies The GPRS feature must be unrestricted.
Syntax
Change command strings
chg_element tlli_blk_coding <value> <location> <cell_desc>
chg_cell_element tlli_blk_coding <value> <cell_desc_opt>
Display command strings
disp_cell <cell_id> [“full”]
disp_element <location> <cell_desc>
Values
Value type Boolean
Valid range 0 Always use CS1 for GPRS TBFs for TLLI blocks, and MCS1 for EGPRS TBFs for TLLI blocks.
1 Use the commanded coding scheme for all blocks.
Default value 0 The default is 0 because commanding the mobile to use the lowest coding scheme (CS1 or MCS1) during contention resolution increases the probability of establishing the uplink TBF successfully in all RF conditions in the cell.
8._cell_data
Description
Force GPRS MS only using GPRS timeslot, until the usage up to _cell_data defination
it's develop parameter to disable GPRS User using EGPRS timeslot, pls use carefull.
Syntax
disp_ele _cell_data, 0 <site number> cell=4 6 0 0 0 **** ****
chg_cell_ele _cell_data, 0 <value> 4 6 0 0 0 **** ****
比较重要，尽量减小GPRS用户对EDGE用户的影响
9. n_avg_i
Description
The n_avg_i parameter specifies the number of signal strength measurements that is made for each filtered interference signal strength sample. n_avg_i is the number of radio blocks that the signal strength is computed on over a period of t_avg_t when in Packet Transfer mode, and
t_avg_w when in Packet Wait (idle) mode.
Type A (no operator actions)
Supported by OMC-R GUI Yes
Cell description required Yes
Dependencies This parameter can be used only if the GPRS feature is unrestricted.
BSS software processes using this parameter are notified immediately the change is made. Syntax
Change command strings
chg_element n_avg_i <value> <location> <cell_desc>
chg_cell_element n_avg_i <value> <cell_desc_opt>
Display command string
disp_element n_avg_i <location> <cell_desc>
Values
Value type Integer (number of radio blocks)
Valid range 0 to 15
Default value 2
根据被测小区的接收信号稳定程度有关，接收电平稳定的可以适当减小
二．BSS级别的参数
10．delay_dl_rel_dur and delay_ul_rel_dur
●delay_dl_rel_dur
Description
The delayed downlink Temporary Block Flow (TBF) release duration BSS parameter,
delay_dl_rel_dur, sets the number of block periods for which the network delays the release of a downlink TBF.
One block period equals 20 ms.
Type A (no operator actions)
Supported by OMC-R GUI Yes (Read-Write)
Cell description required No
Dependencies The GPRS feature must be unrestricted.
Syntax
Change command strings
chg_element delay_dl_rel_dur <value> <location>
Display command strings
disp_element delay_dl_rel_dur <location>
Values
Value type Integer (20 ms block periods)
Valid range 15 to 600 Number of block periods in which the network delays the release of a downlink TBF.
Default value 50 (1000 ms)
该参数设置时间长短对下载的稳定性作用较明显
●delay_ul_rel_dur
Description
The delay_ul_rel_dur parameter is used to configure the delayed uplink Temporary Block Flow (TBF) release duration.
The delay_ul_rel_dur parameter is configurable on a per BSS basis.
Type A
Supported by OMC-R GUI Yes
Cell description required No
Dependencies GPRS must be unrestricted.
Operator actions None
Syntax
Add/Change command strings
chg_element delay_ul_rel_dur <value> <location>
Display command strings
disp_element delay_ul_rel_dur <location>
Values
Value type Integer (20 ms block period)
Valid range 0 to 50 Number of block periods in which the network delays the release of an uplink TBF.
Default value 18 (360 ms).
11．gprs_sched_beta
Description
The gprs_sched_beta parameter sets the scheduling beta algorithm at the BSS when the GPRS feature is unrestricted.
A range error is displayed if an attempt is made to change this parameter to anything other than 1 Type A (no operator actions)
Supported by OMC-R GUI Yes (Read-Write)
Cell description required No
Dependencies This parameter can only be set to a value of 1.
Syntax
Change command string
chg_element gprs_sched_beta 1 0
Display command string
disp_element gprs_sched_beta 0
Value
Value type Integer
Valid range 0 to 2
0 Each MS throughput in bit/s is the same (see NOTE below).
1 THP weighted distribution of overall bandwidth after all interleaving mobiles have met their MTBR. MTBR is 0 when QoS is disabled.
2 MS with higher coding scheme is preferred (see NOTE below).
Default value 1
TBF调度算法，2表示优先保证高编码方式的用户的吞吐量。