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Suggestion to improve HSPA Throughput


#1

Hi Guys!
Lets discuss some proven methods like parameter optimization, features, strategies to improve HSPA throughput and help each other.

Looking forward to hear from all of you experts out there.


#2

Hello @UnREAL

Your topic is a lot embracing (‘proven methods like parameter optimization, features, strategies to improve HSPA throughput’), but let’s try the .50 cents. :slight_smile:

I assume you’re talking about cell throughput.

There are several factors that affect the HSPA cell throughput, and HSPA traffic volume depends on the number of users and also code usage.

So, let’s comment on main factors that impact HSPA performance:

  • Carriers: number and used strategy. For example, you can have 2 carriers (F1 and F2) both for all services. Or you can have F1 carrier for all services (Voice, R99, HSDPA & HSUPA) and F2 for HSDPA and HSUPA only.
    The lesson learned here is that the less handover between F1 and F2 will help overall user experience and get a higher throughput.

  • IuB / IuPS: whether it’s over IP or ATM; If the utilization is OK (no bottleneck).

  • CE & Power Utilization: if there’s congestion, one option is to expand board.

  • Reduce INTER an IRAT Neighbors: because this kind of neighbor uses CM (compression mode) therefore affect the power. The more Handover you reduce, the more improved your HSDPA throughput will be.

  • RF Conditions: elimiate any poor EcNo region (cleaning any interference, RTWP…)

  • PDSCH Codes: number per cell. Maximize it to 15 per cell.

  • HSCCH Codes: number and configuration (if allocation is dynamic or static). The configuration is either in RNC and NodeB. Usually it is static in RNC and open (dinamyc) at NodeB.

  • HSDPA Users: maximum number (configured).

  • HSDPA Scheduling Algorithm. Common option is ‘Round Robin’, that is, each users is served no matter the RF Conditions. Of course for a user in the cell edge it will be good, but certainly will affect cell throughput - lowering it. A better option is to use ‘Proportional Fair’. In this scheduling algorithm the RF Conditions are evaluated, and users with better RF conditions are served more often - making cell throughput higher (compared to Round Robin).

  • ACK/NACK Power Optimization: seeking to find NACK failure. NACK failure is a big problem, because it would invoke RLC layer retransmissions from RLC, which will add to further latency and more retransmissions while when we have an ACK failure, we would just have a simple retransmission. NACK% acceptable values are about 10%; if values too different from this, the scheduler is not working on its best. (Check ACK/NACK ratio of HSDPA counters in NodeB)

  • Features related to HSPA+: mainly 64QAM (enabled) and Load Balancing (enabled). There are many others, most Vendor Specific.

  • Equipment and License: whether it support high throughput, and very important - if there are available license on the NodeB.

Of course there are other checks to perform, but if you have above itens ok chances are you’ll get a fine HSPA cell throughput.

So let’s give a chance for other friends to join us, and share any good experience with an action that gave good results in practice to improve the HSPA cell throughput.

Maybe sharing your experience with some topic listed above, or even a new one.

BR,

RFSpecialist.


#3

Hi, Why the CM and Inter-Frequency affect the Throughput?