What is the difference between HSUPA and HSDPA

HSPA - high-speed package access

HSPA (High Speed ​​Packet Access) is an extension of UMTS. HSPA achieves higher data rates by means of a higher packing density (higher-quality modulations) and several spatially separated transmission streams, as they are also used in WLANs with MIMO technology.

Originally, transmission rates of 384 kBit / s in the downlink direction and 64 kBit / s in the uplink direction were planned in the UMTS cellular network. Since these data rates were too low in the medium term, the data rate should be increased significantly. Finally, UMTS started with the promise to enable a data rate of up to 2 Mbit / s. With HSPA, this promise is finally being kept. There are two protocol additions to achieve this.

  • HSDPA (High Speed ​​Downlink Packet Access) for the downlink
  • HSUPA (High Speed ​​Uplink Packet Access) for the uplink

Both methods can distribute the data load in the base station more effectively and, depending on the quality of the radio link, use a more highly compressed coding method. Both methods also accelerate the response times of the UMTS network.
For HSDPA and HSUPA, however, appropriate end devices (cell phones and data cards) are required.
Since the effort and costs were considerable, HSPA was implemented in several stages.

Note: The terms HSPA and HSDPA are often found in the literature. Both are not the same. HSDPA is part of HSPA. When people talk about HSPA, they basically mean HSDPA. If HSPA is related to the second expansion stage, then HSDPA and HSUPA are meant.

The HSPA standard includes HSDPA and Enhanced Uplink (not to be confused with HSUPA). The WCDMA standard has thus been expanded to include additional transport and signaling channels, which lead to higher system capacity. In addition, network resources are bundled and better modulation methods are used.

Network architecture

While in a UMTS cell only about three to four subscribers can use the cellular network at a reasonable transmission rate at the same time, HSDPA increases the capacity of the UMTS cell to 15 users.
The extensions by HSDPA only affect the UTRAN and the UE. The core network is not affected. However, due to the increasing transmission rate, the core network and the connection of the base stations (Node-B) must also be expanded. Many Node-B are connected to the core network with an E1 line (2 Mbit / s). If HSDPA is really implemented there and if several participants really want to use 1.8 Mbit / s or more, then the line to the core network with only 2 Mbit / s would be far too low. The network operators not only have to upgrade the base stations, but also the connections to the core network. This is not only a lengthy but also an expensive proposition. At the latest when HSPDA comes with 3.6 Mbit / s or 7.2 Mbit / s, the base stations must be optimally supplied.

HSPA specification speeds

The following speed data relate to the theoretical maximum. The higher transmission rates are mainly due to the fact that more bits per second are transmitted per hertz and radio cell.

HSPA + and LTE follow in the further development stages of the 3GPP specifications:

Overview: UMTS technology

Other related topics:

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