So it looks like in the latest 3GPP RAN meeting finally more than 2 carriers have been proposed for Carrier Aggregation. The TDoclist has a few items on 3 carriers for CA. In some cases its been specified that there is 1 uplink component carrier (1UL CC) but in other cases its not specified and I have not looked into details. Its good to finally see more than 2 carriers being discussed.
Now there is a possibility that we may have 2 contiguous bands and 1 band from an Inter-band so the naming would be accordingly. There are also going to be new carrier types (NCT), Band 29 for example. See details here.
Finally, If you want to learn more about Carrier Aggregation (CA) or other LTE-Advanced features, my article from last year, here, would be useful.
Based on the success of the recent posts on eMBMS, here and here, this final post on this topic is a look at physical layer perspective from Test and Measurement point of view. Slides kindly provided by R&S
Some months back R&S held a technical forum where there were many interesting talks and presentations. They have now uploaded video of all these presentations that can be viewed on their website (no embedding allowed).
The 3GPP TS 36.211 LTE standard defines antenna ports for the downlink. An antenna port is generally used as a generic term for signal transmission under identical channel conditions. For each LTE operating mode in the downlink direction for which an independent channel is assumed (e.g. SISO vs. MIMO), a separate logical antenna port is defined. LTE symbols that are transmitted via identical antenna ports are subject to the same channel conditions. In order to determine the characteristic channel for an antenna port, a UE must carry out a separate channel estimation for each antenna port. Separate reference signals (pilot signals) that are suitable for estimating the respective channel are defined in the LTE standard for each antenna port.
Here is my table that I have adapted from the whitepaper and expanded.
The way in which these logical antenna ports are assigned to the physical transmit antennas of a base station is up to the base station, and can vary between base stations of the same type (because of different operating conditions) and also between base stations from different manufacturers. The base station does not explicitly notify the UE of the mapping that has been carried out, rather the UE must take this into account automatically during demodulation (FIG 2).
If there is another way to show this physical mappings, please feel free to let me know.
The R&S Whitepaper is available here if interested.
Free online LTE Tutorial is available at IEEE Communications Society Website, courtesy of Rohde & Schwarz. You can view the tutorial here.
Not long back, I saw R&S demo of CMW-500 with the LG UE at the LTE World Summit. R&S has also verified ETSI 3GPP LTE TTCN-3 test cases with Qasara and has shown successful interoperability testing between Qasara’s Virtual UE and Rohde & Schwarz's 3GPP LTE Virtual Tester.
There is also a LTE TDD Technology Overview available to download from their website here.
In the past year or so there has been lot of talks about the next generation wireless technology and the significance toward adopting these technologies. One of such technology which is very much a popular discussion these days is LTE. Over the last one year LTE air interface and its architecture has become clearer. Significant developments have been made in finalising the LTE architecture and OFDMA and SC-FDMA as radio access technology. LTE as a technology has a come long way in terms of finalising the air interface and other standards. 3GPP1 and 3GPP2 is working hard to get the latest specification out so that telecomms companies start drafting their plans in order to implement the technology.
Giants like Nokia, NTT DoCOMO, Ericsson, Vodafone and others have already started their research and development on LTE thus giving enough indication that LTE is going to be the technology adopted by most as a next generation wireless technology.
Long-term evolution (LTE) promises to make everything from mobile-video sharing to music downloads speedier, but it may not show a visible boost in sales for the network equipment industry any time soon, as the first networks are not expected for two years and many operators will wait longer until the technology matures.
Verizon Wireless, the number-two US mobile service, has decided to build out an LTE network, while China Mobile, the world's biggest mobile provider, said earlier this year it would test LTE. Alcatel-Lucent and Japan's NEC signed a joint-venture deal to pool their development and marketing of the technology. Even Qualcomm has promised chips for LTE, a competitor to its own Ultra Mobile Broadband technology.
Ericsson recently unveiled a glimpse of what the future of mobile Internet will bring, announcing its new M700 mobile platform, capable of LTE (Long Term Evolution) data transfer speeds. Ericsson says this is "the world's first commercially available LTE-capable platform", and we have no choice than to believe it, especially since the Swedish company sustains the platform will bring data transfer speeds of up to 50Mbps (when uploading) and up to 100Mbps (when downloading). Sure, these speeds are not comparable with the ones achieved by NTT DoCoMo's Super 3G network (250Mbps), but they are obviously better than what the current 3G networks can offer. Moreover, these new speeds can surpass, in some cases, the data rates achieved by fixed lines, allowing the development of real-time mobile services, including video streaming and on-line gaming.
Nokia Siemens has already achieved speeds up to 173 Mbps with LTE in a trial of the LTE wireless data network. The field trial was conducted in an urban environment and was meant to test the performance of LTE in "real" environments. This is in contrast to a demonstration of the technology a year ago that achieved speeds up to 160 Mbps.
LTE technology is competing with WiMAX to deliver high speed mobile networks, and both have high profile supporters worldwide. The LTE project was designed to evolve the current 3G technology used today, and Erissson’s prototype together with the Nokia Siemens test shows clearly which camp the companies are in.
There are others who like Ericsson putting a lot of efforts in LTE and thus making it clearer that they prefer LTE as compared to WiMax.
During its first quarter conference call with investors, Alltel announced that it was committed to evolving its network to LTE over the next five years. The move makes Alltel the second biggest CDMA carrier in the U.S., after Verizon Wireless, to commit to the LTE standard, even though LTE was originally on the GSM evolution path. "We do currently plan to move towards LTE in the three-to-five year timeframe vs. WiMAX, but we're still early in that," President and CEO Scott Ford said during the call.
Huawei Technologies ("Huawei"), a leader in providing next generation telecommunications network solutions for operators around the world, has already announced that it has joined the Long Term Evolution / System Architecture Evolution (LTE / SAE) Trial Initiative ( LSTI ) and will hold the infrastructure vendor seat of the 2008 LTE/SAE Trial Initiative Steering Board. The LTE/SAE Trial Initiative brings together major telecom vendors and operators, committed to driving the development of next-generation, high-performance, mobile broadband networks and 3rd Generation Partnership Project (3GPP) LTE and SAE technologies. Huawei's active in LSTI reflects commitment to contributing significantly to the development of HSPA, HSPA+ and LTE technologies, as a leading global telecommunication solutions supplier.
Looking at the trends and developments in LTE, vendors has already started lashing out on LTE licensing.
Rohde and Schwarz is also not lagging behind in it’s efforts to make sure that its system simulators are available for the vendors when they are ready to test their first LTE device. By including the latest revisions of the 3GPP LTE standard in the firmware for its signal generators, Rohde and Schwarz is already offering highly flexible testing for LTE equipment. Rohde and Schwarz has added channel coding and MIMO precoding for up to four transmit antennas to its industry-leading signal generators for LTE (uplink and downlink) Whether mobile equipment manufacturers are looking for an all-in-one solution for 2x2 MIMO signals and real-time fading or simply need standard-compliant RF or baseband signals, Rohde and Schwarz offers the answer.