What Is an HSDPA Modem?

High Speed Uplink Packet Access ( HSUPA) is a mobile communication protocol, which was developed because of insufficient HSDPA upload speed (only 384Kb / s), also known as 3.75G , which is at a 5MHz The transmission rate on the carrier can reach 10-15 Mbit / s (if MIMO technology is used, it can reach 28 Mbit / s), and the upload speed can reach 5.76Mb / s (using 3GPP Rel7 technology, up to 11.5 Mbit / s). Functions that require a large amount of upload bandwidth, such as two-way live video streaming or VoIP, are successfully implemented, so they are better than 3.5G in detail. The telecommunications operators have also stated that the service will be launched between the end of 2007 and 2008.

The first HSPA specification supports increasing peak data rates up to 14 Mbit / s in the downlink and 5.76 Mbit / s in the uplink. Compared to the original WCDMA protocol, it also reduces latency and provides five times the system capacity in the downlink and twice the system capacity in the uplink.

High-Speed Downlink Packet Access (HSDPA) is an enhanced 3G (third generation) mobile communication protocol in the High-Speed Packet Access (HSPA) series. HSDPA is also called 3.5G, 3G + or Turbo 3G. It allows networks based on the Universal Mobile Telecommunications System (UMTS) to have higher data speeds and capacities. HSDPA was introduced in 3GPP Release 5, and it also provides a new bearer of 384 kbit / s with the improvement of the uplink. The previous maximum load was 128 kbit / s. HSDPA also reduces latency, which reduces application round-trip time. The evolved high-speed packet access (HSPA +) introduced in 3GPP Release 7 further increases data rates by adding 64QAM modulation, MIMO and dual-carrier HSDPA operations. Under 3GPP Release 11, even higher speeds of up to 337.5 Mbit / s can be achieved.

The first phase of HSDPA is specified in 3GPP Release 5. The first phase introduces new basic features aimed at achieving a peak data rate of 14.0 Mbit / s and significantly reducing latency. The increase in speed and latency reduces the cost per bit and enhances support for high-performance packet data applications. HSDPA is based on shared channel transmission. Its main features are shared channel and multi-code transmission, high-order modulation, short transmission time interval (TTI), fast link adaptation and scheduling, and fast hybrid automatic repeat request (HARQ). Other new features include High Speed Downlink Shared Channel (HS-DSCH), Quadrature Phase Shift Keying, 16 Quadrature Amplitude Modulation and High Speed Media Access Protocol (MAC-hs) in the base station.

Upgrading to HSDPA is usually just a software update for WCDMA networks. Generally, voice calls usually take precedence over data transmission.

High-Speed Uplink Packet Access (HSUPA) is a 3G mobile phone protocol in the HSPA series. This technology is the second important step in the evolution of UMTS. It was specified and standardized in 3GPP Release 6 to increase the uplink data rate to 5.76 Mbit / s, expanding capacity and reducing latency. Coupled with other improvements, this creates opportunities for many new applications, including VoIP, uploading pictures, and sending large emails.

HSUPA has been replaced by new technologies, further increasing the transfer rate. LTE provides rates of up to 300 Mbit / s for the downlink and 75 Mbit / s for the uplink. Its evolved LTE Advanced supports a maximum downlink rate of more than 1 Gbit / s.

The enhanced uplink adds a new transmission channel to WCDMA, called the enhanced dedicated channel (E-DCH). It also has several improvements similar to HSDPA, including multi-code transmission, shorter transmission time intervals, faster link adaptation, fast scheduling, and fast hybrid automatic repeat request (HARQ) with incremental redundancy, Makes retransmissions more efficient. Similar to HSDPA, HSUPA uses a "packet scheduler", but it operates on a "request-authorization" principle, where the user equipment (UE) requests permission to send data, and the scheduler decides when and how many UEs are allowed to do so. The transmission request contains data about the status of the transmission buffer and the queue at the UE and its available power headroom. Unlike HSDPA, however, uplink transmissions are not orthogonal to each other.

In addition to this "scheduled" transmission mode, the standard also allows a self-initiated transmission mode from the UE, denoted as "non-scheduled". For example, non-scheduled mode can be used for VoIP services, and even reduced TTI and Node B-based schedulers will not be able to provide very short delay times and constant bandwidth required.

Each MAC-d flow (ie, QoS flow) is configured to use a scheduled or non-scheduled mode. The UE independently adjusts the data rates of scheduled and non-scheduled flows. The maximum data rate for each non-scheduled flow is configured when the call is established and usually does not change frequently. The power used by the scheduling flow is dynamically controlled by Node B through absolute authorization (consisting of actual values) and relative authorization (consisting of single up / down bits).

At the physical layer, HSUPA introduces new channels E-AGCH (absolute grant channel), E-RGCH (relative grant channel), F-DPCH (fractional DPCH), E-HICH (E-DCH mixed ARQ indicator channel), E-DPCCH (E-DCH dedicated physical control channel) and E-DPDCH (E-DCH dedicated physical data channel).

E-DPDCH is used to carry E-DCH transmission channels; E-DPCCH is used to carry control information related to E-DCH.

Main article: Evolved high-speed packet access

Evolved HSPA (also called HSPA Evolution, HSPA +) is a wireless broadband standard defined in 3GPP Release 7 of the WCDMA specification. It provides an extension to the existing HSPA definition, so it is backward compatible with the original Release 99 WCDMA network version. Evolved HSPA provides data rates up to 42.2 Mbit / s in the downlink, 22 Mbit / s data rates in the uplink (every 5 MHz carrier), with multiple-input, multiple-output (2x2 MIMO) technology and Higher order modulation (64 QAM). With Dual Cell technology, these technologies can be doubled.

HSPA + has been widely deployed among WCDMA operators since 2011, with nearly 200 commitments

There are different versions of HSUPA that define different data speeds.

HSUPA Category	Max Uplink Speed
Category 1	0.73 Mbit / s
Category 2	1.46 Mbit / s
Category 3	1.46 Mbit / s
Category 4	2.93 Mbit / s
Category 5	2.00 Mbit / s
Category 6	5.76 Mbit / s
Category 7 (3GPP Rel7)	11.5 Mbit / s

Countries and regions that have or plan to use HSUPA networks ^[1] :

• China Mainland

• China Unicom

• Hong Kong

• 3

• Macao

• 3

• CTM

• Taiwan

• Chunghwa Telecom

• Big Brother of Taiwan

• Far Telecom