LTE = Long Term Employment

some very good light readings about NAS.

http://layers7.blogspot.com/

I've been seeing this VoLGA term for a while in LTE related news or articles, but I never bother to find out what it's really about. After checking out some materials from VoLGA forum website today, I guess it looks like a soluton which tries to provide Voice/SMS services through incumbent 2G/3G core-network(MSC/VLR, HSS, MSC server, etc), and it treats E-UTRAN as an access network same as UTRAN/GERAN. This may be fast solution for providing traditional services, but IMS based approach(OneVoice) is more revolutionary and seems to have more support from major players. I think IMS makes more sense because LTE is designed to be all-ip and architecturally flat which matchs IMS by nature.

number of transmitting antennas is also the essential information that's carried in MIB, but not in a direct way as dl-bandwidth, PHICH config and SFN. Instead this information is implicitly broadcased by scrambling the MIB transport block with different CRC bits and each CRC corresponds to certain number of transmitting antennas.

"UE怎么知道该法哪种PUCCH的格式呢？
PUCCH有format 1,1a,1b,2,2a,2b
UE如何知道这个指示信息呢？

谢谢"

my answer:

发送什么格式的PUCCH完全是UE根据需要在PUCCH上发送什么上行控制信息来决定的，如果UE要发SR，能发格式1；如果UE要发 ACK/NACK，只能是格式1a/1b，如果要发CQI或者CQI+ACK/NACK，则只能是2/2a/2b. 这个格式不是eNB调度的！
eNB可以很容易区分对于某个UE收到的PUCCH信息是什么信息。例如每个UE其配置的SR resource index是不同的，那么在PUCCH物理RB中的位置也不同，那么eNB可以很容易知道当前某UE是否发送了SR；ACK/NACK也一样，跟 PDCCH中CCE的位置是有mapping关系的，eNB在哪个CCE下发了该UE的下行调度信息，那么在PUCCH的什么位置上去收ACK/NACK 也就知道了。。

所谓的盲解是UE对于下行PDCCH的，eNB对于PUCCH是所有信息（来自多个UE）都要接受，哪里要什么盲解。

http://bbs.itgoal.com/viewthread.php?tid=16583064&extra=page%3D1

the block-wise spreading is used for PUCCH, the main idea of BS is to divide the whole subcarriers into smaller blocks and using spreading matrices to spread the data across these blocks and thus achieve multipath diversities

here is a block diagram

Here are some good LTE relevant blog feeds I've been following

3G and 4G Wireless Blog http://3g4g.blogspot.com/feeds/posts/default

4G - Your 4G Resource http://www.4g.co.uk/index.php?format=feed&type=rss

LTE Watch http://ltewatch.blogspot.com/feeds/posts/default

Wired n Wireless http://wired-n-wireless.blogspot.com/feeds/posts/default

WirelessMoves http://mobilesociety.typepad.com/mobile_life/atom.xml

Unfortunately most of these blogs are blocked in China, but you can get around by using https google reader to access them. 

In today's discussion, a question was raised: is a DRB bi-directional or uni-directional? The question sounds basic and simple, but no one is sure about the answer.

The description of RLC entity indicates that UM entity is either transmitting OR receiving, while AM entity is both transmitting AND receiving. we know each RLC entity has a corresponding DRB, which may imply that DRBs corresponding to UM entities are uni-directional and those corresponding to AM entitites are bi-directional.  

If that's the case, a user's voip session may typically need 2 UM DRBs, one for voice packets out and the other in. But i'm pretty sure that only one 1 UM DRB exists for a voip 2-way session. So the right explanation seems to be that all DRBs are Bi-directional(so are EPS bearers), and a UM DRB has two correspoding RLC entities (one transmitting and one receiving) while a AM DRB has one corresponding RLC entity which is both transmitting and receiving.

BTW, in 36.509 the loopback testing is designed for DRBs, so it also suggests that DRBs are bi-directional.

Anyone has more thoughts?

【求助】Logical Channel Group的解释？
在36.321的5.4.5Buffer Status Reporting中看到对一个Logical Channel Group（LCG）进行buffer status报告，一个LCG里的logical channel 是不是有相同的优先级呢？不同的LCG就象征着不同类型的LC吗？？

我的回复：

建议你看看36.331里的LogicalChannelConfig信元。eNB在建立一个DRB或者logical channel时，要分配一个优先级（16级）及其所属的LCG（4个）。设置LCG的目的主要是减少BSR报告的粒度，一个LCG内的LC不一定都是相同的优先级，但是理论上应该把优先级接近的LC放在一个group内，这样在由于BSR上报资源不够而只能报告一个LCG的资源需求时（truncated BSR），能保证高优先级的一组LC的资源需求得到及时反映

http://bbs.itgoal.com/viewthread.php?tid=16581993&extra=page%3D1

Anchor Carrier

• No official definition yet. Some related proposals to look into:
  R1-091966
  R1-092061
  By configuration designated anchor carrier would provide system information, synchronization and paging for a certain cell.
  R1-094605

Backwards Compatible Carrier

• R1-092575
  A carrier accessible to UEs of all LTE releases. Can be operated stand-alone or as a part of carrier aggregation

Non-Backward Compatible Carrier:

• R1-092575
  A carrier not accessible to UEs of earlier LTE releases, but accessible to UEs of the release defining such a carrier. Can be operated stand-alone or as a part of carrier aggregation.
  Carrier Aggregation
  TR36.814
  where two or more component carriers are aggregated, is supported by LTE-Advanced in order to support wider transmission bandwidths e.g. up to 100MHz and for spectrum aggregation

Carrier Indicator

Carrier Activation/Deactivation

Extension Carrier

• R1-092575
  A carrier that is not operated stand-alone, but must be a part of a component carrier set where at least one of the carriers in the set is a stand-alone-capable carrier.
  Carrier Segment
  RAN1 58bis Chairman’s Notes
  “Carrier segments, if specified, are defined as the bandwidth extensions of a Rel-8 compatible component carrier (<110RBs) and constitute a mechanism to fully utilize frequency resources in an efficient and backwards compatible way complementing carrier aggregation means. The notion of a carrier segment allows for arbitrary resource block aggregation within one component carrier, retaining the backward compatibility in the part of the composite component carrier bandwidth. Carrier segments are always linked to one component carrier and can not be stand-alone. They do not provide synchronization signals, system information or paging, and therefore can not be used for random access or UE camping.”
• R2-096309
  “Carrier segments, if specified, are defined as the bandwidth extensions of a Rel-8 compatible component carrier (no larger than 110 RBs in total) and constitute a mechanism to utilize frequency resources in case new transmission bandwidths are needed in a backwards compatible way complementing carrier aggregation means. The gain is to reduce additional PDCCH transmission that would be required in a carrier aggregation setting as well as the use of small TB sizes for the part corresponding to the segment.
  The notion of a carrier segment allows for aggregating additional resource blocks to a component carrier, while still retaining the backward compatibility of the original carrier bandwidth. Carrier segments are always adjacent and linked to one carrier and can not be stand-alone. They do not provide synchronization signals, system information or paging.

PDCCH Monitoring Set

• R1-095056, RAN1 59 Chairman’s Notes
  1. A set of DL CCs on which the UE is required to monitor the PDCCH
  2. Size is less than or equal to the size of the UE DL CC set and comprises only CCs that are in the UE DL CC set
  3. Updating of PDCCH Monitoring Set (how dynamic) requires further study

Special Cell

UE DL Component Carrier Set:

• R1-092575
  The set of DL component carriers configured by dedicated signaling on which a UE may be scheduled to receive the PDSCH in the DL

UE DL Component Carrier Set:

• R1-092575
  The set of UL component carriers configured by dedicated signaling on which a UE may be scheduled to transmit the PUSCH in the UL