HSPA, HSDPA and HSUPA: What is High-Speed Packet Access?

Have you ever noticed the ‘H’ or ‘H+’ symbol on your mobile phone screen when using mobile internet? That is HSPA or High-Speed Packet Access. When you see this symbol on your mobile phone, you can expect decent mobile data speeds but remember that HSPA is not 4G.

High-Speed Packet Access (HSPA) is an enhancement introduced in 3G UMTS mobile networks to enable high-speed internet through 3G SIM-enabled cellular devices. HSPA is a combination of HSDPA and HSUPA and can provide peak download speeds of up to 14.4 Mbps and peak upload speeds of up to 5.76 Mbps.

HSPA – Combination of HSDPA and HSUPA

High-Speed Packet Access or HSPA is an umbrella term that refers to High-Speed Downlink Packet Access (HSDPA) and High-Speed Uplink Packet Access (HSUPA). HSDPA and HSUPA are enhancements introduced in WCDMA-based UMTS networks that provide the 3G evolution path for 2G GSM networks.

The original 3G UMTS networks (Universal Mobile Telecommunications Systems) can provide peak downlink speeds of up to 2 Mbps and peak uplink speeds of up to 128 kbps. HSPA was introduced in the UMTS networks to increase the download and upload speeds. It combines two inter-related technologies, HSDPA (High-Speed Downlink Packet Access) and HSUPA (High-Speed Uplink Packet Access). HSDPA was introduced in 3GPP Release 5, and HSUPA was specified in 3GPP Release 6. HSPA saw an enhancement as part of 3GPP Release 7, which is referred to as Evolved HSPA or HSPA Evolution. As a mobile phone user, HSPA is shown as the ‘H’ symbol and HSPA Evolution (Evolved HSPA) is shown as H+. When a mobile phone shows the ‘H’ symbol, it is served by both HSDPA and HSUPA enhancements. HSDPA and HSUPA are available on mobile phones and data cards (e.g. USB dongles and Mi-Fi routers).

What speeds do you get with HSDPA and HSUPA?

HSDPA (High-Speed Downlink Packet Access) is a 3G UMTS network enhancement that provides high-speed mobile data for downloads with peak data rates of up to 14.4 Mbps; HSUPA (High-Speed Uplink Packet Access) is a 3G UMTS network enhancement that can enable upload speeds of up to 5.76 Mbps.

We need to distinguish between peak and average data rates when comparing mobile data speeds. The peak speed is the maximum speed the mobile network can technically enable. In contrast, the average speed is what a user generally gets after the signal has travelled from the base station to multiple user devices simultaneously. The peak data rates with HSDPA are 14.4 Mbps for downloads, and the peak data rates with HSUPA are 5.76 Mbps for uploads. In 3GPP Release 7, a further enhancement was made to HSPA to improve the data rates further. This enhancement is called Evolved High-Speed Packet Access or HSPA Evolution, and it can enable peak downlink data rates of up to 42 Mbps and peak uplink data rates of up to 11.5 Mbps.

For comparison, CDMA2000 networks use a similar technology called EVDO or EVolution Data Optimised. EVDO can enable peak downlink data rates of up to 14.7 Mbps and peak uplink data rates of up to 5.4 Mbps.

What are the average speeds with HSDPA, HSUPA and HSPA+?

As a general rule, you can expect average download data rates of between 3 and 5 Mbps with HSDPA and between 5 and 8 Mbps with HSPA+. The average upload data speeds are between 1 and 2 Mbps with HSUPA and around 3 Mbps with HSPA+.

HSPA and HSPA+ seem good enough for most of our day-to-day internet tasks based on the peak rates. However, we don’t get peak data rates on our mobile devices because the cell within the network that serves us also simultaneously serves many other mobile users. In addition, the network coverage (signal quality) can also impact the data speeds. Below are some screenshots for HSPA+ from a few speed tests carried out in the UK.

–Average speeds for Evolved High-Speed Packet Access or HSPA Evolution (HSPA+) in the UK—

How HSDPA and HSUPA work in HSPA and HSPA+?

HSDPA and HSUPA add new capabilities to the 3G UMTS (Universal Mobile Telecommunication System) networks for FDD and TDD deployments. The focus of HSPA (HSDPA and HSUPA) is higher bit rates and lower latencies. As part of 3GPP release 5, HSDPA introduces a new high-speed downlink channel shared between multiple users. It uses a much shorter transmission duration of just 2 milliseconds than over 10 ms in the original UMTS (3GPP Release 99). As a result, it is much quicker at switching users and responding to the changing radio network conditions. It also uses faster data traffic scheduling which allows it to allocate most of the available cell capacity to one user so that they receive high-speed data in a short space of time. HSDPA can flexibly use the QPSK or 16 QAM modulation schemes to utilise radio network resources efficiently. In addition, it uses superior coding techniques and faster retransmission of erroneous data packets. The decisions on the modulation schemes, scheduling, coding etc., are determined by the Channel Quality Information (CQI) measurements that the mobile phone (UE = User Equipment) provides to the network.

The upload data rates in HSPA are improved by the HSUPA enhancement that adds a new radio interface for uplink communication. Unlike HSDPA, which uses a shared channel, HSUPA employs a dedicated channel for communication between the mobile phone and the base station (Node B). HSUPA also benefits from faster retransmission of erroneous packets, just like HSDPA. Evolved HSPA or HSPA Evolution (H+) is the enhancement added to HSPA as part of 3GPP Release 7, which is further improved in release 8. HSPA+ employs a higher-order modulation scheme, 64 QAM for downlink and 16 QAM for uplink, advanced antenna technology MIMO (Multiple Input Multiple Output), reduced power consumption and layer 2 radio link enhancements.

As a mobile phone user, if your service provider has a GSM-based mobile network (as opposed to CDMA), they use UMTS for 3G network services. To access the HSPA services, you need a 3G phone or device that supports the UMTS technology. Nowadays, with 4G LTE networks, you do not need to rely so much on HSPA, but you are likely to encounter this technology if you are in a geographical area with limited 4G coverage. You may also experience the 2G technologies GPRS or EDGE in remote areas. If your operator uses a CDMA network (as opposed to GSM), then the HSPA-equivalent technology for you will be EVDO (EVolution Data Optimised). I have written a dedicated post on EVDO to help you learn how CDMA networks enable high-speed data.

Here are some helpful downloads

Thank you for reading this post. I hope it helped you in developing a better understanding of cellular networks. Sometimes, we need extra support, especially when preparing for a new job, studying a new topic, or buying a new phone. Whatever you are trying to do, here are some downloads that can help you:

Students & fresh graduates: If you are just starting, the complexity of the cellular industry can be a bit overwhelming. But don’t worry, I have created this FREE ebook so you can familiarise yourself with the basics like 3G, 4G etc. As a next step, check out the latest edition of the same ebook with more details on 4G & 5G networks with diagrams. You can then read Mobile Networks Made Easy, which explains the network nodes, e.g., BTS, MSC, GGSN etc.

Professionals: If you are an experienced professional but new to mobile communications, it may seem hard to compete with someone who has a decade of experience in the cellular industry. But not everyone who works in this industry is always up to date on the bigger picture and the challenges considering how quickly the industry evolves. The bigger picture comes from experience, which is why I’ve carefully put together a few slides to get you started in no time. So if you work in sales, marketing, product, project or any other area of business where you need a high-level view, Introduction to Mobile Communications can give you a quick start. Also, here are some templates to help you prepare your own slides on the product overview and product roadmap.

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