TDLS 被 Wi-Fi 聯盟選為新認證標準，旨在改善串流媒體體驗

TDLS 被 Wi-Fi 聯盟選為新認證標準，旨在改善串流媒體體驗:

Wi-Fi 聯盟之前已經為我們帶來了不少好用的東西，這次新推出的 TDLS（Tunneled Direct Link Setup，通道直接鏈路建立）標準也是如此。這項標準可以讓兩台裝置在無線網路下直接點對點相連，和之前的 Wi-Fi Direct 相比也多了一些不一樣的功能，比如說可以在背景運行並以此來最佳化裝置的表現等。TDLS 甚至還可以在使用 Wi-Fi Direct 連接的情況下啓用，兩台匹配的裝置會自動測量訊號強度，然後選擇最合適的方法相連。此外還有一點很厲害的是，TDLS 可以直接跳過無線網路基地台（Access Point），允許裝置採用其支援的最快標準（802.11b / g / n 等）。Wi-Fi 聯盟表示 TDLS 是一個基於用戶的標準，並不需要對基地台做什麼升級，而且其支援電視、平板、手機、相機和各種遊戲裝置，預計對改善串流媒體體驗能起到不小的作用。雖然到目前為止僅有幾款試驗產品問世，但在像 Broadcom、Marvell、Realtek 這些品牌的參與下，TDLS 應該會有一個不錯的未來吧。

Digest 2012-07-12

- The disadvantage (of channel-orthogonality-based VMIMO user pairing) is that it only considers the orthogonality of the MIMO channel matrix itself, while each user’s SNR are not considered. It may occur that the paired users achieve a high data rate for one, and a low data rate for another, for whose channel fading is severe, which is called near-far interference effect, reducing the system channel capacity. [YSong'12] (VM)

Digest 2012-07-11

- Downlink MU-MIMO = SDMA [Li'09CM]

- Uplink MU-MIMO = collaborative spatial multiplexing (C-SM) [Li'09CM]

- UE must be able to decode the data with a BLER below 10 percent. [Liu'12CM]

- PMI and RI jointly represent the spatial directions of the MIMO channel, while CQI indicates the strength of the corresponding spatial directions. [Liu'12CM]

- PMI and/or CQI may be reported either wide-band or on a subband-specific level (the RI is always reported wideband). [Liu'12CM]

- In scenarios where channel reciprocity is valid (e.g., TDD), the UE transmits a specified pilot also known as a sounding reference signal (SRS) based on which the eNB can estimate the channel. Even in this case, CQI feed-back by the UE is necessary to convey the interference conditions at the UE. These can clearly not be inferred from uplink transmissions. [Liu'12CM]

- Opportunistic scheduling: schedule a transmission, at any scheduling instant, to a user with the best channel condition. [Hur'12TSP]

- There are two main methods for Feedback reduction: feedback rate reduction related to quantization, and feedback number reduction related to reducing the number of parameters being fed back. [Hur'12TSP]

- The resource block size is assumed to be known and can be determined at the medium access control (MAC) layer taking into account the number of users in a system. In practice, it is determined by the standard, for example 12 subcarriers in LTE and 24subcarriers in 802.16e. [Hur'12TSP]

- CQI of user- at block- depends on the diversity technique, the noise variance and channel. [Hur'12TSP]

Hilarious jokes-Village blacksmith

Hilarious jokes-Village blacksmith:

The village blacksmith, Joe was looking for an apprentice and was happy to find his wife's brother Pip, who was willing to work hard for long hours.

Joe immediately began giving instructions to Pip, "When I remove the shoe from the fire, I'll put it on the anvil; and as soon as I nod my head, you hit it with this hammer."

Pip, the apprentice did exactly as he told. Now Pip is the village blacksmith.

SC-FDMA

[Ratasuk'11VTCF] System Performance of Uplink Multi-User MIMO in LTE

Really funny jokes-Double positive

Really funny jokes-Double positive:

Professor Kachwala, a linguistics teacher at Narsee Monjee was in the middle of his lecture.

He said, "In English, a double negative forms a positive. However, there are some languages like Russian, in which a double negative remains a negative. But there is not a single language in the world, in which a double positive can convey a negative."

Asad, a student, sitting in the last bench retorted, "Yeah, right."

Hunting blues

Hunting blues:

Two Harley Davidson riders, Nick and Joey, were riding through the country to go bear hunting. They came upon a divider in the road where a sign read "BEAR LEFT".

So they shrugged and went back home.

4M 2012-02-12 [08.10.50] 變成小花臉