Communication devices such as wireless devices may be also known as e.g. user equipments (UEs), mobile terminals, wireless terminals and/or mobile stations. A wireless device is enabled to communicate wirelessly in a cellular communications network, wireless communications system, mobile communication system, or radio communications system, sometimes also referred to as a cellular radio system, cellular network or cellular communications system. These networks and systems are typically part of, or correspond to, what commonly is referred to as a telecommunications system. The communication may be performed e.g. between two wireless devices, between a wireless device and a regular telephone and/or between a wireless device and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the cellular communications network. The wireless device may further be referred to as a mobile telephone, cellular telephone, laptop, Personal Digital Assistant (PDA), tablet computer, just to mention some further examples. The wireless device may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data, via the RAN, with another entity, such as another wireless device or a server.
The cellular communications network covers a geographical area which is divided into cell areas, wherein each cell area is served by at least one base station, e.g. a Radio Base Station (RBS), which sometimes may be referred to as e.g. “eNB”, “eNodeB”, “NodeB”, “B node”, or BTS (Base Transceiver Station), depending on the technology and terminology used. The base stations may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. A cell is the geographical area where radio coverage is provided according to a Radio Access Technology (RAT) and at a carrier frequency by the base station at a base station site. The base station may support one or several communication technologies, including RATs. Cells may overlap so that several cells cover the same geographical area. By the base station serving a cell is meant that the radio coverage is provided such that one or more wireless devices located in the geographical area where the radio coverage is provided may be served by the base station. One base station may serve one or several cells. When one base station serves several cells, these may be served according to the same or different RATs, and/or may be served at same or different carrier frequencies. The base stations communicate over the air interface operating on radio frequencies with the wireless device within range of the base stations.
In some RANs, several base stations may be connected, e.g. by landlines or microwave, to a radio network controller, e.g. a Radio Network Controller (RNC) in Universal Mobile Telecommunications System (UMTS), and/or to each other. The radio network controller, also sometimes termed a Base Station Controller (BSC) e.g. in GSM, may supervise and coordinate various activities of the plural base stations connected thereto. GSM is an abbreviation for Global System for Mobile Communications (originally: Groupe Special Mobile). In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), base stations, which may be referred to as eNodeBs or eNBs, may be directly connected to other base stations and may be directly connected to one or more core networks.
UMTS is a third generation mobile communication system, which evolved from the GSM, and is intended to provide improved mobile communication services based on Wideband Code Division Multiple Access (WCDMA) access technology. UMTS Terrestrial Radio Access Network (UTRAN) is essentially a radio access network using wideband code division multiple access for wireless devices. High Speed Packet Access (HSPA) is an amalgamation of two mobile telephony protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), defined by 3GPP, that extends and improves the performance of existing 3rd generation mobile telecommunication networks utilizing WCDMA. Moreover, the 3GPP has undertaken to evolve further the UTRAN and GSM based radio access network technologies, for example into evolved UTRAN (E-UTRAN) used in LTE. Standards resulting from standardization by 3GPP may commonly be referred to as 3GPP standards.
The expression downlink (DL) is used for the transmission path in the direction from the RAN to the wireless device. The expression uplink (UL) is used for the transmission path in the opposite direction i.e. from the wireless device to the RAN.
Demand for higher wireless capacity is increasing very fast, particularly indoor where many bandwidth demanding applications are being used, e.g. including watching streaming video and/or uploading video content. At the same time it is in such environments also a relative large amount and often high density of users compared to many more mobile environments and situations. It is therefore an increasing need and demand for increased possibility to be able to serve wireless devices in indoor environments and with comparatively high capacity in both the downlink and uplink.