Showing posts with label HSUPA. Show all posts
Showing posts with label HSUPA. Show all posts

Monday, 11 January 2010

Technologies and Standards for TD-SCDMA Evolutions to IMT-Advanced

Picture Source:



























For Wireless Relaying see the ZTE paper here (



Wednesday, 5 August 2009

12 megapixel Sony Ericsson Satio coming next month

What can you do with a 12 megapixel camera in the phone? I for sure would be doing 'Megapixel Microscopy' and probably click 4-5 photos in a year.




The Phone has 7.2Mbps HSDPA and 3.6Mbps HSUPA capability. There is a different model for US, China and the rest of the world. Thankfully it comes with 8GB SD card so you wont have to worry about transferring your images after every 10-15 photos.

The phone is going to be available in Sep 09 in UK and probably elsewhere.

Sunday, 5 April 2009

Orthogonality and non orthogonality

Multiple access (MA) is a basic function in wireless cellular systems. Generally speaking, MA techniques can be classified into orthogonal and non-orthogonal approaches. In orthogonal approaches, signals from different users are orthogonal to each other, i.e., their cross correlation is zero, which can be achieved by time division multiple-access (TDMA), frequency-division multiple-access (FDMA) and orthogonal-frequency division multiple-access (OFDMA). Non-orthogonal schemes allow non-zero cross correlation among the signals from different users, such as in random waveform code-division multiple-access (CDMA), trellis-coded multiple-access (TCMA) and interleave-division multiple-access (IDMA).

First and second generation cellular systems are dominated by orthogonal MA approaches. The main advantage of these approaches is the avoidance of intra-cell interference. However, careful cell planning is necessary in these systems to curtail cross-cell interference. In particular, sufficient distance must exist between re-used channels, resulting in reduced cellular spectral efficiency.

Non-orthogonal CDMA techniques have been adopted in second and third generation cellular systems (e.g. CDMA2000 and uplink WCDMA). Compared with its orthogonal counterparts, CDMA is more robust against fading and cross-cell interference, but is prone to intracell interference. Due to its spread-spectrum nature, CDMA is inconvenient for data services (e.g., wireless local area networks (WLANs) and 3GPP high speed uplink/downlink packet access (HSUPA/HSDPA) standard) that require high single-user rates.

Communication services can be classified into delay sensitive and insensitive ones. A typical example of a delay-insensitive service is email. Typical examples of delay-sensitive services include speech and video applications. For delay insensitive services, rate constraints are relatively relaxed for individual users and maximizing the throughput by orthogonal methods is a common strategy. The maximum throughput can be achieved by a one-user transmission policy, where only the user with the largest channel gain is allowed to transmit. This implies time domain orthogonality as adopted in many WLANs. For delay-sensitive services, on the other hand, each user must transmit a certain amount of information within a certain period and maximizing the throughput is no longer an appropriate strategy. Rate constraints must be considered in this case.

CDMA is the most well known non-orthogonal technique. The main advantages of CDMA are its robustness against fading and cross-cell interference, and its flexibility in asynchronous transmission environments.
An uplink data transfer mechanism in the HSUPA is provided by physical HSUPA channels, such as an Enhanced Dedicated Physical Data Channel (E-DPDCH), implemented on top of Wideband Code Division Multiple Access (WCDMA) uplink physical data channels such as a Dedicated Physical Control Channel (DPCCH) and a Dedicated Physical Data Channel (DPDCH), thus sharing radio resources, such as power resources, with the WCDMA uplink physical data channels. The sharing of the radio resources results in inflexibility in radio resource allocation to the physical HSUPA channels and the WCDMA physical data channels. In CDMA, which is a non-orthogonal multiple access scheme, the signals from different users within the same cell interfere with one another. This type of interference is known as the intra-cell interference. In addition, the base station also receives the interference from the users transmitting in neighbouring cells. This is known as the inter-cell interference.

Uplink power control is typically intended to control the received signal power from the active user equipments (UEs) to the base as well as the rise-over-thermal (RoT), which is a measure of the total interference (intra- and inter-cell) relative to the thermal noise. In systems such as HSUPA, fast power control is required due to the fast fluctuation in multi-user (intra-cell) interference. This fast fluctuation will otherwise result in the well-known near-far problem. Moreover, as uplink transmission in an HSUPA system is not orthogonal, the signal from each transmitting UE is subject to interference from another transmitting UE. If the signal strength of UEs varies substantially, a stronger UE (for example, a UE in favourable channel conditions experiencing a power boost due to constructive short term channel fading such as Rayleigh fading) may completely overwhelm the signal of a weaker UE (with signal experiencing attenuation due to short term fading). To mitigate this problem, fast power control has been considered previously in the art where fast power control commands are transmitted from a base station to each UE to set the power of uplink transmission.

When an orthogonal multiple access scheme such as Single-Carrier Frequency Division Multiple Access (SC-FDMA), which includes interleaved and localized Frequency Division Multiple Access (FDMA) or Orthogonal Frequency Division Multiple Access (OFDMA), is used, multi-user interference is not present for low mobility and small for moderate mobility. This is the case for the next generation UMTS i.e. LTE system. LTE system employs SC-FDMA in uplink and OFDMA in downlink. As a result in the case of LTE, the fluctuation in the total interference only comes from inter-cell interference and thermal noise which tends to be slower. While fast power control can be utilized, it can be argued that its advantage is minimal. Hence, only slow power control is needed for orthogonal multiple access schemes.

Thursday, 2 April 2009

Fundamental difference between HSDPA and HSUPA

It has been long time since HSDPA and HSUPA came into existence. Untill now we have read and implemented many features related to HSDPA and HSUPA. However following are the basic difference between HSDPA and HSUPA:
  • In the downlink, the shared resource is transmission power and the code space, both of which are located in one central node, the NodeB. In the uplink, the shared resource is the amount of allowed uplink interference, which depends on the transmission power of multiple distributed nodes, the UEs.
  • The scheduler and the transmission buffers are located in the same node in the downlink, while in the uplink the scheduler is located in the NodeB while the data buffers are distributed in the UEs. Hence, the UEs need to signal buffer status information to the scheduler.
  • The WCDMA uplink, also with Enhanced Uplink, is inherently non-orthogonal, and subject to interference between uplink transmissions within the same cell. This is in contrast to the downlink, where different transmitted channels are orthogonal. Fast power control is therefore essential for the uplink to handle the near-far problem. The E-DCH is transmitted with a power offset relative to the power-controlled uplink control channel and by adjusting the maximum allowed power offset, the scheduler can control the E-DCH data rate. This is in contrast to HSDPA, where a (more or less) constant transmission power with rate adaptation is used.
  • Soft handover is supported by the E-DCH. Receiving data from a terminal in multiple cells is fundamentally beneficial as it provides diversity, while transmission from multiple cells in case of HSDPA is cumbersome and with questionable benefits as discussed in the previous chapter. Soft handover also implies power control by multiple cells, which is necessary to limit the amount of interference generated in neighbouring cells and to maintain backward compatibility and coexistence with UE not using the E-DCH for data transmission.
  • In the downlink, higher-order modulation, which trades power efficiency for bandwidth efficiency, is useful to provide high data rates in some situations, for example when the scheduler has assigned a small number of channelization codes for a transmission but the amount of available transmission power is relatively high. The situation in the uplink is different; there is no need to share channelization codes between users and the channel coding rates are therefore typically lower than for the downlink. Hence, unlike the downlink, higher order modulation is less useful in the uplink macro-cells and therefore not part of the first release of enhanced uplink.

Friday, 27 February 2009

Dual-Cell HSPA in Release 8 and beyond












If you want to explore this topic further see:

Thursday, 17 July 2008

HSUPA is here

T-Mobile recently launched HSUPA network here in UK:

T-Mobile said, in certain areas, upload speeds will be five times faster than previously. It claims upload speeds of up to 1.4 Mbps. T-Mobile UK chief executive Jim Hyde said: "Mobile broadband has come of age. Today, 25 per cent of new contract customers are signing up and we expect to quadruple our user base in 2008.

"We knew mobile broadband would burst on to the scene and our continued investment in new technology is paying dividends for customers seeking a fast, consistent service which offers great value."

T-Mobile has also upgraded its HSDPA network, it said. It now boasts download speeds of up to 7.2Mbps within the M25.

Meanwhile, T-Mobile Germany has annoucned the completion of the HSPA upgrade to it's 3G network, meaning that customers can now download (HSDPA) at 7.2Mbps. The plan is that the upload speed (HSUPA) will be boosted to 2Mbps by the end of the year.

In other news, AT&T in USA plans for 2008 include the completion of the nation's first High Speed Uplink Packet Access (HSUPA)-enabled network by the middle of the year. The AT&T 3G network now delivers typical downlink speeds ranging between 700 Kbps (kilobits per second) and 1.7 Mbps (megabits per second), and it will now offer faster uplink speeds ranging between 500 Kbps and 1.2 Mbps. The faster uplink speeds allow AT&T's HSUPA-enabled laptop users to quickly send large files and take full advantage of the latest Internet and business applications.

An article in TelecomTV claims that Mobile Social Networking may be the killer application for the promised HSUPA:

This is the year for HSUPA, or High-Speed Uplink Packet Access, according to leading provider of the enabling technology, Qualcomm. HSUPA is the companion standard to HSDPA (the high speed downlink standard) and enables 3G users to upload large files - especially still photos or videos - in seconds rather than minutes.

Qualcomm says that while HSUPA used to be allocated only to the high end chipsets (for use on high end phones) it's now being included as standard for chipsets aimed at 'mid range' devices and by the end of the year will appear as standard on low end phones as well.
Why the adoption spurt? Mobile social networking and user generated contents are the main reason. Where many traditional data applications, such as receiving email, web browsing, and music and video downloading are overwhelmingly asymmetric (far more data coming down than going up) the coming mobile social networking wave looks likely to demand huge amounts of uplink capacity as users begin to use the features of their new upscale phones in earnest. High resolution multi-megapixel cameras mean big, chunky picture files; easy video capture means even larger video files; and new applications involving pictures and location, via GPS, require high quality, reliable connectivity back to the controlling server.

According to Qualcomm, mobile social networking will finally and resoundingly answer the question: Why do we need 3G?

We'll need it because the evidence shows that users are interested in taking social networking out of the confines of the tethered PC, and putting it on the road via their mobiles where it can blend with and enhance real, physical, non-virtual social networking: the sort which involves real people moving about and doing things in real places.

So users are fast moving beyond SMS and towards applications and services which will enable them to really share their activities at, say, live events.

So let HSUPA roll and let the fun begin.

Friday, 2 May 2008

All about F-DPCH







Thursday, 31 May 2007

3G -> 3.9G

Lets first start with 2G systems:
2G = GSM
2.5G = GPRS
2.75G = EDGE
Then moving onto 3G systems:
3.5G = HSDPA
3.75G = HSUPA
3.8G = HSPA+ (HSPA Enhancements)
3.85G = 'HSPA+' + MIMO
3.9G = LTE