"The higher layer signaling may indicate that a CC is a host CC that is able to transmit the PDCCHs of client CCs, the predefined format for the DCI in the PDCCHs for the host CC having a non-zero-bit carrier indication field.
"Thus, PDCCHs containing carrier indicators are only transmitted on a subset of CCs (say K, where K=1, . . . , M and M is the total number of CCs aggregated for the UE), called the host CCs.
"The higher layer signaling may indicate that a CC is a client CC that does not transmit the PDCCHs of other CCs, the predefined format for the DCI in the PDCCHs for the client CC having a zero-bit carrier indication field.
"The PDCCHs of client CCs can be transmitted on a host CC. It is possible for a CC to be a host CC as well as a client CC at the same time. In this case, the CC can transmit the PDCCHs of other CCs as well as having its own PDCCHs transmitted on other CCs.
"The higher layer signaling may indicate that the UE is not required to detect PDCCHs on a client CC. Instead, the PDCCHs for the client CC are transmitted in the host CC. The method may then further include the step of selectively reading the PDCCHs of CCs so that the UE does not detect PDCCHs on that client CC.
"A client CC can thus be configured such that all PDCCHs (with zero-bit carrier indicator) for a UE are not transmitted on the CC. Hence, the UE is not required to detect any PDCCH on the client CC. However, such configuration cannot be applied if the client CC is also a host CC at the same time.
"This configuration is beneficial for heterogeneous networks deployment where the interference level of the client CCs can be so high that control channels cannot be reliably transmitted. As PDCCH detection is not required for the client CCs, power saving can be achieved at the UE.
"However, for other deployment scenarios such as homogenous networks where frequency diversity gain may be more important, the diversity gain can be harnessed by the UE also detecting PDCCHs on the client CCs.
"The higher layer signaling may not indicate that a CC is a client CC or host CC, in this case, the CC may be taken to be a normal CC which is used to transmit all of its own PDCCHs and only its own PDCCHs, the predefined format for the DCI in the PDCCHs for the normal CC having a zero-bit carrier indication field.
"Thus, using higher layer signaling, an eNodeB can configure a CC to be one or more of the following types: Host CC: The CC which can be used for transmission of the PDCCHs of client CC(s) and its own PDCCHs. Client CC: The CC of which its PDCCHs can be transmitted on a host CC. The client CC can also be used to transmit its own PDCCHs if configured to do so. Normal CC: The CC which is used to transmit all of its own PDCCHs and only its own PDCCHs (same as in LTE Rel-8).
"All PDCCHs transmitted on the host CCs always contain carrier indicators with non-zero bits, even for the PDCCHs that correspond to the host CCs. The actual number of bits for the carrier indicator field can be a function of the actual number of carriers aggregated for the UE (i.e. ceil(log 2 M).). The PDCCHs transmitted on the client CCs or the normal CCs do not contain carrier indicators with non-zero bits.
"The higher layer signaling may be used to configure CCs as host CCs, client CCs and normal CCs in a semi-static manner according to need or change in the radio channel characteristics in the network. For example, for a heterogeneous network with uncoordinated deployment of femto cells, the interference characteristics of each CC may change several times in a day.
"The higher-layer signaling may be UE-specific, as some UEs may not have carrier aggregation capability. Furthermore, for a heterogeneous network, the interference characteristics for each CC experienced by different UEs may be different. As shown in FIG. 1, UE 16 and UE 18 clearly experience different radio characteristics for CC #0 and CC #1.
"The host CC may have the same CC bandwidth as a client CC for which they are transmitting PDCCHs. In this case, a CC which is a part of carrier aggregation has to have the same bandwidth size with at least one other CC within the carrier aggregation for it to be eligible as a candidate CC for a host or a client CC.
"Advantageous Effects of Invention
"The advantage of the invention is that the number of PDCCH blind decoding attempts that the UE has to perform for the host CC does not double due to two different payload sizes for the same DCI format as a result of the difference in CC bandwidth. In conjunction with using the predefined formats as described above, the number of blind decoding attempts required to be performed by the UE may be kept the same as that needed for a normal CC."
For more information, see this patent: Ng,
Keywords for this news article include: Electronics,
Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2013, NewsRx LLC
Most Popular Stories
- Networks Vie for U.S. Hispanic TV Viewers
- Ad Counts Rise in 2013 for Hispanic Magazines
- 2014 World Cup Official Noisemakers Quieter than Vuvuzelas
- Saab Gets Back into the Game; U.S. Auto Sales Soar
- Dell Offers Undisclosed Number of Employee Buyouts
- Authorities Close to Deal with JPMorgan Chase over Madoff Response
- Apple Activates Customer-Tracking iBeacon
- 2013 Tech Gift Guide: iPad Mini Still Hot; Chromecast a Great Low-Cost Option
- A Biography of Jonathan Ive, Apple's Creative Chief
- Top Websites for U.S. Hispanics