4G/5G TA/TAL Planning Principle

 TA/TAL Planning Principle

The TAC or TAL planning for 5G is similar to 4G. Infact, as the current 5G NR will be using the NSA mode, so initially it should be using the same TAC or TAL as the 4G network. However, the principles for TAC planning are same as given below

The paging load should be calculated to ensure that the TAC is not so big that the paging overhead gets too high. This issue is usually mitigated with the intelligent/dynamic/precise paging features

If the TAC is too small, this will result in a lot of TAUs that can generate signaling overheads. This can be handled by intelligent TAL planning or even user specific dynamic TAL assignments

Some of thumb ruple w.r.t absolute counts 

1. When do TA/TAL planning, need guarantee the TAs do not overlap in different TAL.

2. Suggested TA size do not keep too big, so when do TAL optimization , configuration adjusting is flexible ;

3. Suggested a TA including 30~70 eNBs, and TAL including 3~10 TAL;

4. If operator have 2G/3G network, can consider referring to 2G/3G network LAC border as LTE/NR TAL border mainly because 2G/3G LAC was optimized. For CSFB traffic scenario, the suggestion is necessary to decrease CSFB handover delay.

5. for CSFB scenario, it is also necessary to guarantee TAL don not span MCS or MCS Pool;

6. to decrease TAU spending, the TAL border do not allocate hot traffic spot, suggested TAL border allocating low traffic areas.

7. TAL do not suggested span Serving GW area to avoid ping-pong handover between SGW.

8. TAL do not suggested span MME or MME pool to avoid TAU failure when UE moving between MME or MME pools

TA/TAL Number Principle

1. For TAC, the value range defined by 3GPP specification is from 0 to 65535; and prescribe the value 0(0x0000) and 65534(0xFFFE) as reservation, so when do TA planning, avoid using 0 or 65534.

2. For TAL, the value range defined by specification is from 0 to 65535;

3. For TAC, if the network scale is not sweeping, suggest the TAC is uniquely; otherwise consider using different TAC for city border; and the TAC is uniquely in the same city;

4. For TAL, suggest using uniquely number in the same MME or MME pools, but allow reusing the same TAL number in different MME or MME pools;

TA/TAL Size Suggestion

1. For dense urban or urban, considering LTE deployment scale, suggested including about 200 eNB/gNB for a TAL, max. not exceed 300.

2. For suburban or rural scenario, suggested including about 300 eNB/gNB for a TAL, max. not exceed 580.

3. For LTE/NR deployment scenario based on 2G/3G network, suggested considering LTE/NR TAL border is identical to 2G/3G LAC

4. For intial network deployment phase, suggested a TAL include 5~10 Tas.

to facilitate TA&TAL management , operator can designate the number rules considering all province city in live network ,so when do TA&TAL planning, consult the operator if those constraint rules need be considered