mutation. An open-loop MIMO region is defined as a time-frequency region in which the base stations coordinate their open-loop MIMO transmissions in order to stabilize the interference environment where the precoders and numbers of streams are not time-varying. The open-loop MIMO region with Ns streams uses the Ns-stream pilot pattern and a given open-loop MIMO mode with Ns streams without rank adaptation. The resource units used for the open-loop region are indicated in a downlink broadcast message. These resource units are aligned across cells. A limited set of open-loop MIMO modes are allowed for transmission in the open-loop region (see Table 10-23 and Table 10-24). There is no limitation on the use of any open-loop MIMO mode outside the open-loop region. The logical resource units used for the open-loop region are designated through the AAI_SCD MAC management message. An open-loop region is associated with a specific set of parameters such as the type of open-loop MIMO region (number of streams, MIMO mode, MIMO feedback mode, type of supported permutation). All base stations that are coordinated over the same open-loop MIMO region use the same number of streams in order to minimize interference fluctuation and to improve the CQI prediction at the MS. All pilots are precoded by non-adaptive precoding with Ns streams in the open-loop MIMO region. The CQI measurements are conducted by the MS on the precoded demodulation pilots, rather than on the downlink reference signals. The precoded pilots are transmitted in all the resource units in the open-loop MIMO region even if data is not transmitted by the BS on some or all of those resource units. In order to configure any MIMO mode, one or multiple MIMO feedback modes are specified to indicate the parameters that the mobile station needs to measure and send to the BS through the uplink feedback channels. When allocating a feedback channel, the MIMO feedback mode is signaled to the MS and the MS sends feedback according to the feedback mode. The feedback correspond